This isn't that revolutionary: LastPass already allows you to use biometric ID to authenticate and it works without any changes to the website.
It also doesn't add any security. Your password can still be guessed or phished. When authenticating with a cryptographic token (U2F/WebAuthn), that vector goes away. (Even OTP can be phished... the phishing site can just ask you for the code.) Password managers do make it more difficult to get phished, since they will not know what password to autofill on phishing.example.com... but on the other hand, password manag…
I agree there are advantages to using public key crypto but the reality is that it's more difficult to get right (and therefore not implemented) compared to a simple hashing function for a password.