These lights seem to be ubiquitous in theatre. You're very likely to find them at the front of stages. Sometimes you see them lighting up architecture. But they've never found a home on film sets. At least, I don't think I've seen them there.

Was wondering why this is. Too harsh or hard to control? Not bright enough? Hard to mount? But they're also cheap as chips. Could they not be of use as a hair light or accent light on the set.

Have you ever used them in a video?