As per my 3rd post in this thread...do you have an idea of where you may have got this understanding? I would really like to read a merchant guide to supporting

Pay
Oh my god... It was in one of the many hundreds of posts about Apple Pay...
Basically, if I pay in the UK say an item for £15.20, here's what happens:
NFC terminal to everyone: Any NFC cards nearby?
My card to NFC terminal: I'm here.
NFC terminal to my card: Would you like to pay £15.20 to terminal Costco 137463?
My card to NFC terminal: Yes, here's a code (a code with the information "Gnasher's card", "Costco 137463", and £15.20).
NFC terminal to my card: Let me check that.
NFC terminal to Visa: Here's a code I got; is that Ok?
Visa to itself: "Looks like Gnasher's card".
Visa to NFC terminal: "Got a payment from a valid card to Costco 137463 for £15.20".
NFC terminal to my card: "Consider it paid"
NFC terminal to Visa: "Please send the money to Costco".
Note that the NFC terminal never checked itself whether the card was valid, but Visa checked that. Now with Apple Pay the steps are very similar:
NFC terminal to everyone: Any NFC cards nearby?
My iPhone to NFC terminal: I'm here.
NFC terminal to my iPhone: Would you like to pay £15.20 to terminal Costco 137463?
My iPhone to NFC terminal: Yes, here's a code (a code with the information "fake Apple Pay credit card", "Costco 137463", and £15.20).
NFC terminal to my card: Let me check that.
NFC terminal to Visa: Here's a code I got; is that Ok?
Visa to itself: "Looks like a fake Apple Pay credit card. I see, it matches Gnasher's account, so that's fine".
Visa to NFC terminal: "Got a payment from a valid card to Costco 137463 for £15.20".
NFC terminal to my iPhone: "Consider it paid"
NFC terminal to Visa: "Please send the money to Costco".
If you look at all the lines with "NFC terminal", there is no change at all. The NFC terminal doesn't know it was an iPhone, and never needs to know. Just works. However, it _must_ be an NFC terminal that already accepts cards.
In the UK, there is currently a limit of £20 for NFC purchases. Obviously if you steal my card, you can make NFC purchases, so they need to keep the limit low. I don't know if that limit is built into the card or the terminal. It makes more sense if it is built into the card (because my bank knows what risk they are willing to take, the terminal can't know that), so higher purchases should work without problems if Apple Pay allows it.
BTW. The code that is sent would be encrypted in a way so that only Visa can read it. And if Visa gets one of these "fake" credit card numbers, it takes note of it and makes sure that the exact same code can never be used again. So if someone listens to the messages going on between the terminal and my card, they can get the code that I used, but it won't work a second time. _And_ the code is designed so that only my iPhone can create a code that matches my credit card.