If a system is configured as you describe, that just means that it then effectively has an additional root/admin account, except under a possibly unpredictable

If a system is configured as you describe, that just means that it then effectively has an additional root/admin account, except under a possibly unpredictable name. So security through obscurity, really (if the privileged user name is secret). That might make sense for some small number of setups, but instead it seems to be enormously popular, and often times it is even used in the security-defeating manner of having the "usual" user be privileged.