I agree Donny but when I do those mixed gigs, keyboard and DJ, when I get to the DJ part I really don't want to be in line with one of my main speakers. Just need the monitor for the "live" part. Used to use my Peavey Impulse like that. It plugged into one of the main speakers and when I went to the DJ stuff I'd just turn it face down. I've heard those songs already !!
Thinking the powered one I could turn the volume down in a similiar situation.