Well, I wouldn't want to see a moving head fixture or a scanner get the jelly treatment. But my whole thing are SHOWS and not DJ-type stuff. In a DJ-type event, it can be beneficial to actually have those jelly effects up on the trusses and stands. Not a true "2 in 1" sort of thing, but a neat idea either way.
For me, I prefer lower profile. I don't want to bring attention to the light fixtures more than necessary. I don't mind people KNOW that something is there or even what it is or even what it is doing. I just don't want to bring excessive attention to it because for what I do, it would be a distraction from what people need to focus on.
I'm sure those who want a jelly version(or not) would pay the little bit extra to make sure they get what they want. I also doubt the extra cost would not be a deal breaker for most folks.