Is your mac a server or a multi-user desktop where some users intentionally don't have admin access? If so, you're in trouble. If not, this bug probably doesn't really matter to you.
For a single-user desktop machine, realistically, user/root privilege separation doesn't matter, because all your important data is in your home directory and not protected by root privileges anyhow. The root-protected stuff is actually the stuff that's easiest to replace, because it's just a bunch of software that you can re-install. Viruses don't need to infect your software to stay resident; they can just as easily register a login hook without root permissions.
(That said, some people will violently disagree with me on this.)
For a single-user desktop machine, realistically, user/root privilege separation doesn't matter, because all your important data is in your home directory and not protected by root privileges anyhow. The root-protected stuff is actually the stuff that's easiest to replace, because it's just a bunch of software that you can re-install. Viruses don't need to infect your software to stay resident; they can just as easily register a login hook without root permissions.
(That said, some people will violently disagree with me on this.)