Seems novel. But from a security aspect, if OpenSSH has security vulnerability that allows an unauthenticated user to login, via whatever means, once you are in the system as a non-privileged user, you are now free to use the same vulnerability to get root.
Basically this exercise is like using two locks that have the same key to open them. If the same key opens them, then a weakness in one, is now a weakness in the other so why bother with two identical locks?
Don’t listen to this guy at all.