I think people miss the point that it takes more skill in using a bow then a futuristic aimbot plasma based shoulder weapon that has the capacity to punch a hole into a tank. Have to have strength in pulling back the bow, keeping it steady to launch a successful shot, keep tight groupings for have consistent accuracy, taking account of wind, elevation, getting close enough range to make successful shot without alerting your prey due range limitations of a bow, ect.
I don't know much on the speargun's performance seeing as we have the games to go with and that one scene in Predator 2, so we don't know the true canon function of the weapon will be like the other media or something else new. It came in pistol and rifle form, and for all we know it could have been a wrist weapon that is short ranged due to the ambiguity of the scene in P2. Lets not forget that the speargun's function during gameplay is not an accurate translation to film function due to said being gameplay.
As for cloaking device, I mean we humans use camouflaged suits to blend in the environment for our hunts or warfare operations and this is an advanced version that crumbles before being splashed by water, in comparison to our camosuits that simply get wet but in no means disrupts the suit's function at all. Might rain in the forest but I still blend in said trees in bushes, but just sucks that I'm wet and now a simple wind can get me cold. So its a trade off of strengths and weaknesses.
