I think the use case for this app is for people to store their loyalty cards in the app... Not their credit cards. In most (almost all?) cases the cashier can

I think the use case for this app is for people to store their loyalty cards in the app... Not their credit cards. In most (almost all?) cases the cashier can manually enter the number on the front of the card in to their register. For example, if the magnetic stripe on the back of the card was wearing out or damaged.