What's the intersection of people who are afraid to set up their own wallet, want to use Ethereum and Bitcoin, and are happy to have PayPal as the one performing their transactions for them? Any of those might be reasonable independently, but it's hard to imagine someone fitting all three.

Quite a lot, because you're forgetting one key group - existing Paypal users who are interested in crypto but not interested enough to proactively pursue it.

"Trust PayPal with your not-wallet" oh sure.