I think you're supposed to make a "Pass", load it on Wallet app, then load the card with double press of side button. You can't just tap a blank iPhone and get its raw hardware ID.
At least Suica train cards(based on FeliCa/NFC-F) on iOS can be read from third party Android apps, and Apple do advertise iPhone feature to store corporate IDs, so the idea of using iPhone for gate tap-in card should be completely fine.
At least Suica train cards(based on FeliCa/NFC-F) on iOS can be read from third party Android apps, and Apple do advertise iPhone feature to store corporate IDs, so the idea of using iPhone for gate tap-in card should be completely fine.