That sounds like a good idea. You could use a private key to unlock your password manager.
But the problems of both using 2FA and a private key is that they both rely in something that only you have.
If someone figures out how to steal your phone/hard drive, then they also have their way to all your accounts.
This dial tries to get back to the idea of "something that only you know".
Finally, you could also use a private key with a password, and you would even reduce more the attack surface. But again, the dial is a way to make harder to hear your secret when you're entering it in the computer.
Anyway, this dial is a PITA to enter long passwords, which is not good. Long passwords are very important.
But the problems of both using 2FA and a private key is that they both rely in something that only you have.
If someone figures out how to steal your phone/hard drive, then they also have their way to all your accounts.
This dial tries to get back to the idea of "something that only you know".
Finally, you could also use a private key with a password, and you would even reduce more the attack surface. But again, the dial is a way to make harder to hear your secret when you're entering it in the computer.
Anyway, this dial is a PITA to enter long passwords, which is not good. Long passwords are very important.