As of a few month ago, some hotels are rolling out support for loading hotel keys into mobile wallet apps like Apple Wallet and Google Wallet. These digital cards will use the NFC functionality to open doors similar to how NFC tap-to-pay works.
Some universities are also offering digital ID's (through Google/Apple Wallet) or fully replacing physical student ID's with them, which I presume are also used to access things on campus such as opening doors, campus transportation, etc.
I'm sure many other places will follow suit such as workplaces, apartment complexes, and other private establishments. Who knows, maybe even government buildings, airports, and public transit might switch over. I'm not someone who is aching to replace my physical stuff for obvious reasons, but this seems to be where the world is heading whether I like it or not.
I understand payment cards like credit cards and debit cards won't work. When I tested grapheneos in the past, I got stuck at trying to add a payment card. But would these other non-payment NFC things work? If not, what's the plan here as more places start requiring it? I feel like this should be on GrapheneOS's radar so there is enough time to maybe come up with a solution before these digital cards become mandatory.