Dewey, I was thinking more of the nutrient export, along with the decorative aspect, since I don't have a sump.
I just figured if it got too overgrown, I can always pull it out & bring it to my LFS for her fish there. She almost always has tangs, and blennies, also.
I don't have much in the way of algae eaters, just hermits, although my mollies will nibble on everything (including me!! tickles!). Most of my fish are pretty omnivorous.