Hiya
In my OPINION, they work!!! This is my reasoning: if you look at a spearo dressed in complete black, including your speargun and your long bladed fins, you look like a 4meter+ object in the water. What the cammo does is to break your big shape up. This way you look like smaller to a fish. Well, thats my reasoning!!
Another reason: when laying on the surface, you could very easily be mistaken for a seal. Under the water, we're too clumsy to be mistaken for a seal, but laying on the top, the possibility is there. I'd rather have a cammo wetsuit, so that i'm not confused for a seal!!
And, cammo suits look COOL!!!


Regards
miles