Apparently rewards cards incur an extra charge for the merchant. Which essentially means that that cash back comes right out of the merchant's pocket. I don't mind that at all, but it does mean that the bank isn't "sharing the profit with you."

A debit card/check card/credit card substantially eases access to one's money (or money one doesn't have). So I think it's reasonable that they charge at least some fee for it, though if it turns out my BofA debit card is one of those that require it I will probably never use it again.