At best, its only benefit is cosmetic and bare oxidized aluminum is
fairly invisible as it is. Attempts to "camouflage" it only attract
the eye.

I had some surprising results with flat black paint on antennas.

Would you believe people walking right by a 2 x 3' horn antenna, mounted at
eye level, and not noticing it? Another foot closer, and they would have
walked right into it.

Somehow, flat black makes things "dissapear" against normal backgrounds.
Once you know it's there, you see it.

White paint is much more obvious. We had calls within days after replacing
a repeater antenna. The replacement was in a 1.5" diameter radome, and the
closest viewing point where you can actually see the antenna is about half a
mile away, due to the location of the antenna on the roof, and the height of
the building relative to the surrounding buildings.