Most DJ-friendly venues have a spot for them to set up, but they dont provide the gear.
Wouldnt it be nice if the whole rig could fit in your pocket, instead?
Basically, they took an entire DJ studio and packed it into a controller no larger than most smartphones.
They can be used for everything from sound editing to effects, and transition seamlessly between purposes.
Thats just a guess, mind you the real product could cost significantly less.