I haven't either,but it's there.
I suppose one of the reasons is price.And the fact that one can break the price into two different time periods for example has its own effect.
Another one is one can test a broad range of satellites.
The most obvious one,is what already happens,people try to do that buying subs and then wonder about the lack of impact (not rumble,the upper impact).
But you can't cross a sub at 150-200-300Hz if it's 2 meters away from mains.
See that very interest at the Ascilab thread when people saw a bass module in a blurry photo.
Just a suggestion of course,it's you that run your business.