And there's your blocker. Being limited to only devices from a single vendor is horrible, and a firm no from a lot of people.
> Now we can put on the tinfoil hat and say how this fosters vendor lock
The fact that you call it a tinfoil hat type issue is just insane to me. Literally every person in my household has some apple devices and some other ones (android, windows, etc). And some of them have switched back and forth.
Plus, the "ergonomics" of logging into a website on a random device to check something are awful.
Maybe for a lot of tech people, I don't think the general public understands the risks enough to care.
What would you answer if grandma asked you what happens if she loses her physical key?