I am not sure what you are trying to discuss, but I have already been using a Debit card that draws off my stored crypto coins and is converted into FIAT each time I want to spend somewhere. It is a clean and easy way to get access to my coins for very low costs. There is a cashback fee on each transaction.
In my country when you buy something with your debit card or credit card you get rewards points. If you buy something for example $100 you get maybe 1$ reward points.