Necessary? Not at all. As I stated previously, I am running a much tighter than stock squish gap, aka more compression. Compression = heat. I ride basically how you describe, and have yet to climb into the "danger zone" (400F and above) where the aluminum starts to lose its strength. Heck, my cylinder wall gap with my Meteor piston is about as tight as one would want to go and I have yet to even have a hint at soft seizure.
That all being said, more cooling is never a bad thing in this case.
