From a relative beginner's pov (still white belt ...)
i have only just experienced recently what working with an absolute beginner was like.
And yes, you are perfecting the most basic techniques but it makes you look at these differently. More perfecting rather than basic 'getting grasp of general idea'.
With experienced students I know i am getting more out of the practice than they are. They offer a grasp of skill and immediate options for 'what if' questions that i won't have for a long while yet.
the one thing i, and other relative beginners can give in return is an element of surprise. not often...but on rare occassions the lack of knowledge counters their expectation that we will give boring same old routine response...and wakes 'em up a little.
but I learn different things from different people - not always dependant on their level of skill. more to do with how open they are to learning while teaching or whether they've decided they already know everything...