There appears to be anecdotal evidence to suggest that coral's grow and color better when lit with a light that is heavy in the blue portion of the spectrum. Actinic also makes certain fish and coral fluoresce so it does make the tank look a lot pretty, imo
Do you need them? I guess you don't really *need* them. But like I said earlier, a lot of people believe they are actually good for coral.
I notice that you have both NO and a MH
. You could put actinic's in that NO light strip. I doubt those 50w of NO bulbs are helping much anway since you already have that MH