[Fai Mao]

Because Paypal does not reveal your credit card info to the seller.
It lets people not worry about their CC number being stolen. It is useful if you are a small internet-based vendor. Buyers do not want to give you their CC number and you can’t really take checks or cash.

Paypal is a very secure way to purchase on a site like Ebay or Craigs List.

[Jim from C-Town]

OK. That makes sense.