well, it was included for now for testing purposed only.
But its for e.g. Behringer BCF2000 MIDI control console. It has motoric faders and knobs.
Suppose you use this control fader and Midi director from Fiesta. You can set some fader to control brightness. Now, when you switch between the virtual devices and every device has different brightness, this Midi feedback will send information about brightness back to this control console. So the fader(which controls brightness) moves to correct position.
Also you can use this with effect channels. When you switch between the effects, all the faders and knobs move to correct position(according effect settings)!