[veeti]

That's a nice thought but how does it work in practice? Every time I sign up for a new service I have to dig up my "backup device" from the safe just to enroll it?

Google Authenticator used to be this way: no backup and restore, as if I'm going to spend a day setting up dozens of TOTP codes again and again every time I change phones. Thankfully, sanity has prevailed since then.