It would be a great innovation to incorporate a Card Reader into both iPhones and Apple Watches. The user could open the card reader app on his watch or phone, enter the amount to be paid into his nominated bank account (eg £15) ready for the purchaser/customer to tap his card to make the contactless payment. It would simplify my everyday life enormously because I hardly ever carry cash these days.
Improvement to Future IPhones and Apple Watches
Yes, Apple Pay is need up data.