They are no different IMO than GSP, yellow polyps, or any other corals or critters that people love to hate. Mojanos and aiptasia aren't bad to look at either, but when it (or they) take over, it gets to be a problem. I was getting to a point with the asterina stars that it made my rock look like it had acne or the measels. Literally hundreds upon hundreds of them coating everything in the tank. It was getting to a point where all I saw when I looked in there were small starfish. Plus, they don't grow to a point of being useful for anything, they don't get any bigger than the end of your finger. A few ok, but when they get out of control, you have to do something about them. If anyone really thought you could bag them and sell them, I could make hundreds at a couple bucks a bag......