To me, the whole thing about LED being more efficient....no argument. I think that's a great thing in and of itself....but, I just want potent marijuana and I can get that by growing under any number of types of lights....so can anyone.
I only consume "about a pound" per year (if that) and so the whole idea of one light being more cost effective than the other is relatively meaningless to me. No matter which type of light I choose to grow under, its only going to be used once per year, I might pay a bit more on my electric bill...but, again, not a significant amount to sway me to choose a light based on that, alone.
Something tells me that plants like that "invisible" light -even if they don't use it for photosynthesis....Maybe some plants like the thermal wavelengths for developing other chemicals. Again, I can't say for sure, but I have yet to see many weed plants "complaining" about 1000 watts! I know that some growers have to add heat to their LED grows via a space heater or something. I know I've had to do that on my LED grows. So if I have to add the electricity back into the bill in addition to the efficient LED, then it becomes about the same cost as HID, anyway.