Its already happening. Check out STK (Stack). They have a 5 year deal with Mastercard and have a beta going on right now. The team are ex Mastercard employees as well. On boarding Canadians as we speak. Americans happen at the end of the year.
But how applicable is it in the modern world? I probably did not quite correctly ask the question
I meant when the application of crypto currency will become so common that you can go to the store and buy sneakers or a phone