I suppose they refer to a more detailed mental model. For example, I know that it's a key in my device, but I don't have a detailed enough model to know if it will work if transferred to another device or stored in the cloud, or what I'm supposed to do at a cybercafe/hotel/airport/borrowed computer. So my mental model is not good enough. With passwords, the answers to questions like that are obvious.
That’s the problem. I don’t think that’s part of the spec.
I’m also not sure, and given that there’s no mention of transferring, backing up etc, I assume they’ll be lost forever.
I won’t take that risk. And if they require my email/password/2fa to recover, the. What’s the point.
I wanted to love them so much, but I can’t. I won’t burn myself again like with getting a new phone and loosing all your 2FA, because someone thought it’d be a good idea to make them device bound on most apps.