I am not familiar with Fido but I am looking at their website. It looks like a complex protocol for enterprises. Not some simple library available for many programming language and platforms, which any website can easily implement and add as an alternative or a substitute for login/password.
It might help the google, microsoft and bank of america of this world. But these are not the ones leaking our credentials (most often). It is the smaller websites who will not have the resources to go through some certifications or implement these protocols from scratch.
What is really missing is a common, free standard protocol, that can be easily adopted by a small website.
The protocol is open, so you can create open source lib and server. You do not need to certify the open source libraries. There is already a lot of code out-there. The browser have to implement it as well, chrome does, others should follow soon.
But in general they seem to be doing a very good job of forcing hardware to be standards complaint. They are putting quite a bit of effort into standards testing suites that you can use to validate your code as well.
A good thing about it is that on the server it only saves site-specific public keys, so small websites that get hacked leak important information.
It might help the google, microsoft and bank of america of this world. But these are not the ones leaking our credentials (most often). It is the smaller websites who will not have the resources to go through some certifications or implement these protocols from scratch.
What is really missing is a common, free standard protocol, that can be easily adopted by a small website.
Is Fido trying to answer this use case?