Well another issue with this line of thinking is that the branching high energy species like that are not necessarily there because it's the best place to grow. It could be that they have evolved to tolerate less than ideal conditions. This gives them an edge on competing for space with corals that didn't do that. And again this could simply be a matter of brightness. We really need a controlled experiment to answer the question.Since the par/pur levels on the reefs is much higher then our tanks, but continues to fluctuate, dont you think they would congregate in deeper depths then they do if full spectrum wasn't the preferred choice. I mean they literally have had millions of years to evolve. If the blue spectrum was preferred, they would have evolved to optimize the deeper water even if it was a lower over all pur they received. Many encrusting and soft corals did just that. Branching sps on the otherhand evolved to take advantage of the high intensity full spectrum zones with high surging flow.
This is easily observed on the reefs.