Does a credit card stop you from getting water or food from there?

Maybe you meant bank card: In places where you have a right to a bank account (necessary for payroll and government stuff), you'd get a bank card. In places like the US, most places accept cash.

So no. No it isn't.

I'm not sure this was designed to deter homeless folks, by the way, though I do think they could provide water from somewhere that isn't from the toilet room.

It's just water