This is how it is done for 20 years (by those who truly care about the users).
As many have said before, transmitting the hash simply turns the hash into the password itself. Anyone who has your hash, has your password.
The biggest reason for hashing is that, even if an attacker gets access to the hashed passwords, they still can't use them to log in. Client-side hashing completely and utterly undoes that benefit.
Passwords in transit should be protected by SSL. Not a hash.
Most interestingly, it solves the problem where the server may not be trusted. I see how this would have protected against the Facebook problem.
I'm curious, have any major websites you're aware of adopted SCRAM as a best security practice? It feels kind of like overkill, since generally the server is considered to be trusted... but at the same time, it would definitely prevent accidental logging.