I mean, I don't want to keep funds in PayPal, but they make a good proxy for a credit card.
Credit card POS systems permit for me to do (reasonably, lack a trusted display or input mechanism) secure transactions. But I can't do that with my computer
I don't have a way to use a smartcard reader and purchase things online. I have to send my actual credentials to a vendor and trust that they're treating them securely.
But if you use PayPal to pay at a vendor and then send that payment to a credit card, you avoid the security problems inherent to direct personal use of credit cards.
I'm not comfortable sending credit card data to sketchy-looking sites. With PayPal, worst case they don't send me whatever I paid for.