[rosstamicah]

"Paypal doesn't require this. A buyer can use their credit card. They don't need to sign up for anything."

This is not exactly true. When a buyer uses their credit card they are promoted to add an email address which essentially creates a Paypal account for them. They may never actually log into that Paypal account and use it, but they will have a paypal account with the info they've entered. It's Paypal's sneaky way of signing people up.