So it doesn't generate a second card number like other things I've used?
But anyway it sounds like the answer to my question is no, Apple is not doing anything meaningful per payment. They play a role in setting up a card and that's it. Is that accurate?
When you add a card, your bank creates a device-specific Device Account Number, encrypts it, and sends it to Apple w/ a key used to generate a unique sec code for each transaction.