No doubt the higher light helps with longer distance vis... the thing I am promoting here if you will is that two lights vertically placed seems to be unique to cycling, and thus something that may help identify cyclists specifically...

This is just something that I happened to notice while driving about... that the combination of two lights is both more visible and is unique to cycling. I have not seen two vertical lights on anything else... although it would be easy to have that combination on motorcycles too, but motorcycle riders tend to depend on their built in single light. Cars have their wide horizontal spaced lights, and trucks have their various marker lights. Two vertical lights is unique.