This is my third attempt at forming an argument, which still aint coming.

I say do it although I cant seem to convey any other logic other then that. The air will heat up plenty prior to actually getting to the lamp. Vortex fans tend to warm up a little, plus air can and will adjust temps along the pathway to the light. The cold start would be the only issue I can see, but if your lights are getting down that low when their off, I'd hate to think of what it's doing to your plants. If the plants can make, surely the light will have no complaints either.