Of course you can point Ubuntu users to Ask Ubuntu, but please don't give the impression that this site is somehow for experts only. It is absolutely not only for experts! We already have a problem with some users downvoting newbie questions, as though they were born with knowledge of *nix arcana and were never newbies themselves! We really don't need more people thinking that.
This site does have expert questions, yes. But it also has newbie ones. Our the scope is defined only by the operating system, not by the asker's level of expertise. If you find a question that's very Ubuntu specific, then flag for migration or suggest to the OP that AU might be better. Just please don't justify it by saying this site requires a level of knowledge before you can participate.