sMiles is just one of many apps on the market that you can get “free crypto” for using. There are multiple ways to earn crypto with sMiles. The three main ways are

How sMiles Works
sMiles has multiple facets on how you earn crypto, but one may focus is activity data. sMiles links with your phone’s activity center and automatically imports your activity data. You earn more Bitcoin (satoshi) the more you walk. One thing is that in order to get credit for your activity data you need to give sMiles access to your location data.
You can also earn small amounts of Bitcoin by playing chess and answering surveys. This is a small component of the app and the earnings are very very small. I would bot play the games in sMiles unless you want to play them regardless of the crypto.
How sMiles Makes Money
Very few things in the world are truly free and the same applies with sMiles. The app uses your location data and exercise data in exchange for crypto. The default of the app is to have location on 24/7. You can change it to only when the app is open, but then you must open the app everyday to actually earn crypto.
Country Limitations
The limiting factor with sMiles is having it available in your App Store.
Redeeming Crypto
sMiles has a minimum redemption of 1,000 sats. It will take most people about two months to earn enough Bitcoin in order to be able to redeem it with sMiles
Overall
sMiles will not make you rich. sMiles is not a native crypto that has a chance to go to the moon. sMiles is a way to make a few bucks if you are comfortable selling your location data. The easiest way is to give them access to your location data without having the app open so they can collect if without effort. Using the location data only when the app is open greatly decreases the amount of data you are giving them to sell, but it also increases the effort to get your rewards. If you do not log in once a day, that days rewards disappear.

Signing Up
If you sign up with a referral code you get 100 satoshi. My referral code is pbjclimbing697.