Why rewards stay the same
Apple Pay uses a device-specific number in place of your card number, but the issuer still links the payment to your account.
The merchant code comes from the store's terminal, not from your phone. A supermarket purchase codes as a supermarket either way.
Spending caps, category bonuses and the base rate all apply exactly as they would with the card in hand.
The exceptions
Some cards pay a higher rate when you pay with a mobile wallet. Apple Card is the best-known example, paying more with Apple Pay than with its physical card.
Some issuers have run promotions that add a bonus for mobile wallet purchases in a given period.
Purchases made in-app or online with Apple Pay take the online merchant's code, which can differ from the same brand's physical stores.
The real problem is the default card
Apple Wallet opens on your default card. Double-click to pay, and that card is what gets used, whatever the store.
Switching cards in Wallet takes a swipe, but only if you already know which card to switch to.
CardSwipe answers that question on your Lock Screen, before you open Wallet, so the swipe goes to the right card.
