autocorrect fail: it's "watts"; 250W & 400W are two common size for metal halide lamps.

Unfortunately they are full of mercury and can explode at end of life.

wouldn't that put out a lot of heat? like a lot a lot? that's one of the attractions of LEDs for lighting is they can produce a hell of a lot of light with very little heat coming from the bulb. all of the heat is in the electronics in the back. anything in front of the light will not wilt. of course, i'm thinking in terms of photo/video.

LEDs as you can see in the video aren't as efficient as you might think, since he has a HUGE heat sink / water pump system in place

you're missing the fact that that is the key point. the heat that is generated is not pointed at the person in front of the light. in photo/video, this is huge. talent/models don't sweat from standing in front of the lights. food products don't melt/wilt under the heat either. nobody really cares about the heat pointed away from the subjects.

For photography I agree. But if you're trying to create a "sun at home" because you don't have enough light/no chance to get sunlight, to feel the warm of the light can be nice...