I'm not sure if there's even an API to add store rewards cards as NFC cards, since all of my rewards cards in the Wallet are barcodes.
> These programs are conveyed through NFC via Apple Wallet's VAS protocol. Programs that support One Tap are conveyed at the same time as a payment card stored in Apple Wallet.
https://www.op.fi/private-customers/daily-banking/cards/card...
Other banks in Finland also offer the same loyalty card integration with their payment cards.
No idea how it works technically. I assume that it broadcasts the loyalty card and the debit card at the same time when you use NFC, since you can get both with one (long) tap against the payment terminal. It also reads the loyalty card if you use chip + PIN to pay. The loyalty card is completely separate from the actual payment card - if I use Apple Pay to pay with the same underlying Visa card, it will not give me any loyalty rewards.