Access to a smartphone with NFC can indeed be an issue for some people, but it is still better than having to record videos of yourself holding your ID next to your face, then a couple of years later finding out that your personal data is freely circulating on the web because one of those sleezy identity verification services has been hacked.
That's nice, I was under the impression only ApplePay had access to read and write data via NFC. Still no ability to write arbitrary data via NFC, but for the purposes of this app that's good enough.
The limitation is in the other direction, the iphone can’t be read or written over nfc as if it were a tag by an nfc reader (feature is called host card emulation).
It is technically possible but apple makes it very difficult to get the entitlement. When a project I was working on tried to get it (to enable the use case of unmanned sports and library facilities unlocked by swiping the phone instead of a badge), they failed. Apple basically ghosted us. After a while they simply stopped responding to our questions. This is why we can’t have nice things on iphone.
That was the case for a while, but they've allowed other stuff for a bit now. I've been topping up my public transport smartcard with my phone for, er, three or four years now, I think.
