Just recently, I factory restored my iPhone due to me forgetting the backup password. When I added my card, I noticed that I did not need to call the bank like I did before. But now, it skipped the verification. Anyone know an explanation?
The verification process differs from bank to bank, so it's difficult to give a definitive answer for your particular card. However, Apple sends information from the device to the issuing bank which can be used as part of the verification process. So perhaps the bank recognized that the card was previously successfully verified on that particular phone and approved it without further verification this time.
Here's some related information from the
iOS security guide:
"Additionally, as part of the Link and Provision process, Apple shares information from the device with the card issuer or network, like information about your iTunes and App Store account activity (for example, whether you have a long history of transactions within iTunes), information about your device (for example, phone number, name, and model of your device plus any companion iOS device necessary to set up Apple Pay), as well as your approximate location at the time you add your card (if you have Location Services enabled). Using this information, the card issuer will determine whether to approve adding the card to Apple Pay."