I was wondering this myself the other day during a flight with easy, where the majority of the passengers had hand baggage (as large as possible) and perhaps only 3 passengers were collecting their hold bags from the carousel. I can appreciate that the fast turn arounds might make freight loading/unloading challenging, but to fly with all but empty holds must be frustrating commercially. The weight saving/fuel burn equation can't be so advantageous to negate possible hold freight, but there you go!