Comment by greatgib

The magic of password is that you can write them to paper or keep them in your mind. No interoperability issue if suddenly having to use it temporarily or permanently with another device, like if you lose your phone. And you can also pretend they don't exist and no one can prove otherwise. Also if you don't use a password manager, no one (hacker or else) can extract it from your head like it can be forced from your devices.