They are heaters alright! For years my grow heated my house during the Winter. Now that I've switched to LED I have to pay to heat. Turns out paying for heat saves me some money, not a lot, and I get a more even heat. Which is very subjective. But HID works great, as does LED. When I turn up the dimmer on my LEDs I could likely heat my house but I don't need to turn them up to get optimal growth from my plants.HPS grow tents are the best heaters, lol. They grow weed! Electric wall heaters don't.
Just grow cannabis, LED/HID who cares when you're smoking it