Okay serious?
It's entirely cosmetic. Yes, if you were in a concealed position overwatching enemy movement, having a black gun is easier to recognize. BUT- snipers didn't color their guns from WWI to GWOT, and unsurprisingly they weren't slaughtered. They just threw burlap over it or whatever.
Infantry tactics don't really need camo'd guns, unless it's some really snoopin' n poopin' kind of stuff. Hunters don't need it but it sure looks purdy.
However- dude this is an AR! Do you want a colored gun? Then get it! Celebrate yo' freedom! Coat that sucker! If you've got the cash and have a design in mind, go for it. You'll have the best looking rifle on the range line and you can upload pics to your heart's content.
There's really no other benefit except "because it looks cool." Gun won't shoot any straighter because it's painted FDE.