I somewhat agree, it would be much easier for us. But there are two problems with paypal, one being that it is very expensive and the other that people can just order their money back.
I'm not sure if paypal allows this, but maybe they could make it so the user has to pay the paypal fee (making the paypal option more expensive).
Against people that order their money back they could require a authentication so only the account owner can buy something in the store. Then they could ban accounts that order their money back. Again I'm not sure if paypal allows this.