im pretty sure the reason colorsets are made the most if because they are the easiest to make, and require very little effort (sort of)
the problem that i find with other add ons is
1. i dont understand how to use milkshape
2. i dont understand the code (how to get a gun to shoot a specific bullet and make a specific sound (the .cs file))
to me it just doesnt make sence
but paint sets do, so most people who dont have any idea how to make add ons, will pri make paint sets instead