Clef makes it easy to replace passwords. For example rather then going to login to bitstamp with your username, password, and then 2fa, you can just login using your phone. It is quick and easy.
Bitstamp would need to add the clef plugin.. And trust the central server...
Can this not be done trustlessly? I mean we are on bitcointalk right?
Any 2FA system should be trustless and open source.