Plus they don't need to get up high to be efficient, so you can hang out in less congested airspace without eating up gas, and on shorter flights you don't waste time climbing. Flights like ORD-CVG or ORD-IND, in a CRJ you waste all this time climbing up at 290 to get a few extra knots and fuel efficiency just to come back down after 20 minutes of cruise flight. A turboprop could level off at 20, cruise a few knots slower, and still get there in roughly the same amount of time while using way less fuel.