The classic approach in marketing, aside from telling everyone your service or product is the next best things since sliced cheese, is to show your competitor's option is lower quality. This inherently drives audiences to the idea that your product is better and therefore should be bought if there is a choice. In the case of David Marcus recently stating that Bitcoin (BTC) won't be used to buy things, he and PayPal couldn't be further off the mark. Bitcoin is and will definitely be used to buy things, just not the mainstream consumer level products. There is no question that BTC is one of the most powerful digital assets available for purchasing things and services, they just happen to be at a much higher price tag than where PayPal's realistic market would be.
PayPal Who?
PayPal first came to light, much in thanks to eBay's success, as a digital payment tool that replaced the need for credit card processors. Users online could make a payment with their credit card or bank card, and the seller could accept income without having to be registered with Visa or Mastercard (something that usually costs a couple thousand dollars to set up as a business). PayPal's online service, accessible through an Internet browser and later through mobile devices, was a disrupter of that traditional payment processing model, and quickly opened up e-commerce at the micro-business level. It also went gangbusters when eBay adopted (bought) the service as its primary payment tool, both protecting users as well as making it easier to sell online.
Since those early days of the mid-2000s and earlier (2003), PayPal became an online e-commerce giant for digital payment processing, and for many years enjoyed cornering the market of online consumer payments. PayPal eventually separated from eBay and ultimately was dropped by them as a payment tool. PayPal then expanded its digital footprint taking over Venmo, a popular mobile device payment tool, in 2013. The service has also dipped its foot into crypto, allowing users to buy an equivalent position in the four major coins (BTC, ETH, BCH and LTC), and also now launching its own stablecoin, PYUSD (note, as of 2023 users still don't own their own crypto seeds with PayPal crypto accounts). However, to make the leap that this platform will wipe out BTC as any kind of a payment alternative is just silly.
Why Fixating on BTC as a Payment Option is a Waste of Time
First off, the category of people paying with BTC on an occasional or regular basis are well above the income levels of the average PayPal user, even including small businesses. While the attempt is to obviously convince folks, like the eBay days, that PayPal is the better vehicle for crypto payments, in reality it has no practical utility to the folks who actually pay with BTC right now.
Secondly, why in the world would anyone shift over to PayPal who already uses BTC? They would only be welcoming additional PayPal fees on their transactions versus direct wallet to wallet BTC transactions that already exist on the blockchain.
Third, the strategy misses the target as not being relevant to the folks who do use PayPal for payment processing. In fact, if the company was correctly worried about low-cost digital payment processing competition, it should be focusing its marketing attention on showing why LTC, MATIC and NANO are poor payment tools in the crypto world versus a PayPal approach. All three of those can move large sums lightning fast, with almost nothing in gas fees, and from wallet to wallet consistently. When ETH gas fees were through the roof, those three coins were the classic courier buckets for moving funds to circumvent the otherwise inevitable ETH fee loss. Additionally, PayPal has steady competition online with Google Pay, Apple Pay and Stripe, to name a few.

Realign the Target Where it Matters
No, unfortunately, the marketing focus here is probably crafted by someone who doesn't really understand blockchain that well or how people use it daily. If PayPal really wants to penetrate into digital and crypto payments, it may want to then focus on finding a smoother way to move funds between parties and focus less on trying to throw mud on well-established channels that only cater to well-off and rich. While that group might seem attractive, they pale in comparison to the exponential traffic that the average consumer can produce en masse. Just ask Amazon.