If it can go online, I'd prefer to use an android work (or user) profile with only auth apps in it, and nothing else.
replyAs a separate device, it should be offline always IMO, and perhaps the size of a passkey. Or one of those banking devices with a display that show an authenticated text saying what you are confirming.
What if it was the size of a credit card and it had stuff like your name, date of birth and even a picture of your face. I want to name this invention an ID card…
replyAnd if you added a cryptographic layer to it, with your own private key baked into it, you could both sign the documents, confirm your identity and the government could confirm it's actually you....
reply....wow, that would be reinventing the existing model of the leading ID cards....
Crazy if you think about it :)