Re: I don't fully understand this
"Isn't that just like a bank debit card?"
No, a merchant still needs to deal with a payment processor to take bank debit cards, because it is impossible to be connected to every bank. These retailers want to be able to be paid directly. I have some sympathy for trying to avoid the constant drain imposed by the middle men. So basically these retailers want to connect to every bank, and provide all of the gateway services themselves.