Ask HN: Why are PayPal fees larger than card processing?

Quoting from https://www.paypal.com/business/fees

If the funds you are receiving are coming from a PayPal account: then you pay: In the U.S. a fee of 3.7% of the transaction amount plus $0.30 USD. Outside Canada and the U.S. a fee of 3.9 % of the transaction amount plus a fixed fee based on the currency

I was expecting fees lower than Stripe when customers pay with their PayPal balance, and same as Stripe when paying with cards through PayPal.

How come PayPal is more expensive? Do they rely on customers preferring PayPal instead of sharing their card details with sites (even through it's in a Stripe popup, customers don't know about Stripe)