These wallets have a number of advantages, primarily for ease of use, so they are good for new users. For example, they make use of ENS (Ethereum name service) for human readable public addresses instead of having to use long strings of numbers and letters, which are easier to get wrong, and impossible to remember. In many cases, these wallets don't require private keys or seed phrases for recovery, if you lose your phone or forget your password. They also make it easier to invest in Defi services, especially for novices while retaining custody of your own assets, at all times. You also don't have to deal with metamask, since the dapps are built in to the wallet (in the case or Argent). They also tend to work well on mobile, and you can connect mobile apps to the web using WalletConnect. Here is a good explanation of what smart contract wallets are and how they work.
This wallet is designed for single users (no multisig). They use a concept of trusted guardians for "social recovery". So, instead of recovering your wallet with a private key or seed phrase, you can use a "guardian" (friend or family member) who is on the same platform. You can also set a daily transaction limit for spending. Transactions to trusted contacts don't count towards this limit. Large transactions have to be approved. You can also lock your wallet from a web interface, if you lose your phone. They also have an emergency kit which would allow you to remove your funds if the company disappears, or for some reason the UI doesn't work. (There should always be an alternate way to get your funds out in this rare situation). The smart contracts are opensource and audited, which gives additional assurance. All ERC20 coins are supported. They won't show up in your wallet, unless you deposit or transfer them in.
Argent is designed for a mobile app platform, and the google app store rating is 4.9. For now, they are also paying the gas fees for transactions. The support is responsive and they have active communities on telegram and discord. They support various on-ramps by country to deposit funds from fiat currency. I tried it here, and it directed me to Moonpay, which did some verification but no KYC documents were required. My funds transferred pretty quickly by VISA credit card payment, with about 3.5% of fees.
DeFi apps directly supported in the wallet are TokenSets, PoolTogether, Aave, Uniswap V2 liquidity pools, Compound, Maker and Kyber. I did some testing with small amounts. I was even able to invest without having any eth in my wallet, (since they were paying the fees). Its definitely easy to use, and inexpensive to transact. You can also add your ENS address (xxx.argent.xyz) to a 3rd party Defi monitoring tool like Zapper.fi or Zerion and track your portfolio that way as well, if you want to see it on the desktop. There is also a workaround to do web/desktop transactions in your argent account using wallet connect. You can go to any service that supports wallet connect, and scan the QR code to connect the wallet to the web dapp.
I have only recently discovered this this smart contract wallet, but I really like it. It has many of the same features as Argent, including security, but takes a different approach when it comes to Defi. Instead of trying to integrate the finance apps directly in the wallet, they concentrate on the login and authentication, and allow you to use the Defi apps with the native interface, either on the web, or mobile. If the apps supports authereum directly, it is super easy to connect (like Zapper.fi, or 1inch, or Curve.fi). If not (like Uniswap), you can just connect with wallet connect. It is not smartphone centric like Argent, but it is web responsive. So, you can just create a shortcut in your phone browser, and you can scan the QR code from wallet connect. They are also working on a native android/IOS app which should be even easier. It also has a convenient web interface which works easily on the desktop. And its simple to move to other devices and other apps (both mobile and desktop). They also pay for gas fees for most things, for now, so its inexpensive to evaluate. You can also pay for transaction fees with coins other than eth (such as Dai if you want). I found the onboarding easy as well. The smart contracts are opensource, and on github where they can be audited. Here is a good medium article about the security/private key architecture.
All my testing and evaluation has been very good. In all, a great experience without compromising power or sophistication.
This one is also pretty easy to use, but is more limited than Argent for now. It is primarily designed for mobile use, but there is a desktop interface that can be accessed at https://app.dharma.io/account. You start earning interest as soon as you deposit Dai, at the rates from compound. They do have a debit card, but I believe that it is only supported in the US. They do pay gas fees for deposit and withdrawal. The security model is similar to argent, but they don't have the recovery process thru "agents", it doesn't support ENS addresses, and is limited in terms of the defi services and coins that it supports directly. I expect them to expand this in the future.
This smart contract wallet does have a web, desktop and native mobile version, but the mobile app is limited for now, and is missing some of the important features that the desktop versions have (such as loading existing safes). But you are not able to interact directly with Defi smart contracts which are not on their safe list. It currently supports Compound lending directly, and more defi services will be added soon. The mobile app supports wallet connect, but its hard to get the current mobile app to talk to the desktop app (you have to make the owners the same which isn't straight forward). It doesn't create ENS (human readable addresses) automatically like Argent and Authereum, but does allow multiple users to share a wallet with Multisignature. You can set security policies and spending limits for users. This project has a lot of potential, but has a bigger learning curve than some of the "single user" wallets. It is secure and powerful. All the contracts are opensource and audited, and is used as a base for the Multis product discussed below. You can also buy insurance for your funds at Nexus Mutual. I believe that this wallet is a good choice for experienced users, and also for enterprises. For now, it is more difficult to use with Defi, but that situation should change when the new mobile wallet version is released later this year.
This one is designed for companies, and is based on the source code from an older version of Gnosis. So, it can be accessed from that other Opensource wallet if something were to happen to the company behind it. You have to use a company email address to sign up. It doesn't support automatic ENS addresses, so you have to use the traditional long public keys, but you don't need a private key. It does support multiple users, multiple safes and multi signature. It has a few of the Defi services, and is adding more. You can add any ERC20 coin with its contract address. They don't have a mobile version yet. They are also adding smart contract insurance support with Nexus Mutual. They are targeting companies, and moving to a paid subscription business model to fund future development and profit.
This one is a little different, since it is a smart chain/contract wallet that is running on its own Polkadot parachain. So, in addition to having better security than a standard blockchain wallet, it also has a number of other powerful features. It can be used to hold assets from many different chains like Polkadot, Tron, Eos, Eth etc. And it can do swaps from one to another. In most cases it is faster than eth, and less expensive. There aren't pairs for every asset combination, but the hub supports most combinations with USDT. So, you might have to go thru USDT for some types of swaps, but the transactions are generally fast and inexpensive. In addition, it supports staking for most of the major POS coins. Some are locked in and some you can unstake at any time. I am still testing it, but I have found it to be extremely useful, and I havn't found anything else like it.
Authereum can also be used together with Gnosis, if you need the multi-user/multisig features. Argent is also good, but I am missing the ability to use the wallet on my desktop. After a fair amount of testing and evaluation, I have found that these wallets to be good for both new and experienced users as well. In addition to ease of use, the advanced users can also benefit from better security and convenience. Wallet connect support ensures that you can use virtually any dapp that may not be directly supported already. Paying for the gas fees is a bonus. Also, you can use a "private window" on Brave to get the best privacy so it won't keep any information in the browser, which is a good practise for using Defi services.
But I am sure that all the smart wallets will be improving and adding features, and new ones will appear. Here is a new article that I just found with an overview of the various smart wallets. So, they may leapfrog each other as time goes on, and the best choice will ultimately depend on what features you need, and what your priorities are. But they are all safer than using a standard private key/seed phrase wallet, and they also make it easier to use Defi. Let me know if you have tried any of these smart contract wallets and what you think.