Not only good eating, but I am wondering how they spread, since they are territorial and tend to stick around one particular place. In some areas, sports divers leave a floating marker so the spearfishers can come back and spear them.
Have also read that, in some places,the predators, like groupers, have learned to eat them despite the spines.
Interesting to know. I like the idea of groupers eating them. My son does quite a bit of spearfishing I will ask him if he has seen any markers around here.