A student just picked up a couple of those for a summer theater show. They're a lot of bang for the buck in that kind of low-budget setting; but theatrically the audience is not the target and the lighting instrument itself is not typically visible. This is an instance where the lighting is truly aimed at discreetly enhancing and framing the action on stage.
The thing that really stands out about most DJ lighting is that the fixtures are almost always in the wrong place. That owes largely to the DJs desire to give him/her self a larger than life presence, and to have the actual moving fixtures visible while doing their thing. You're right about the "light in the eyes" annoyance, but when the lighting completely surrounds the DJ rather than the dance floor it's obvious that lighting the floor was never the true intention. Much like the stage lights, the DJ is most interested in how he/she looks - not what the experience on the dance floor is.
Likewise, when you see bands performing at events - their own lighting is also aimed at themselves rather than the dancefloor. Moving heads may scan the whole room during these wedding and other mobiles events, but that's not really the way dance floor lighting is designed for club spaces. In that setting, the dance floor BECOMES the stage and that's where the lights are focused. Other areas in the club have their own unique lighting to match the respective uses of those spaces.
The thing to keep in mind with respect to DJ lighting is that what WE see from the booth - is very different from what the audience sees. When we present our light show as side-lighting it's only the DJ that gets the prime view - everyone else is viewing the dark side of the moon - the shadow side of people on the floor.
I largely agree with you. I will regularly place wash style fixtures at opposite sides of the dance floor so that we get the space covered, and don't place them near the DJ booth at all like this:
It's creating ambiance but not adding to the attention directly around me. And that's how I'm most comfortable. I don't really want to be the center of attention at these events.
But I think a lot of young people are most familiar with DJs from a big name headliner or festival DJ sort of world. If you're used to seeing videos of Tomorrowland (crazy fire!) or EDC... you're used to seeing the DJ as a performer supported by a bunch of lighting and effects... your expectations of what you want is way different.
The sad part about these festivals is that the guests are no longer interacting with each other. They're just watching the performer, jumping a bit, and taking their own crappy iphone videos for no reason at all. But that same experience is how young people are now watching DJs.
I doubt I'll ever do another high school gig based on how they've trended and how much I dislike the experience. But the last one I did... the kids don't even dance with each other. They just jump and sing along to the hooks, and then stare at you.