I am baffled by this, and have been for a long time. The past few years I have been doing lightweight trips (a week long, starting at 32 pounds or so, but ending near 20 pounds) with a MLD exodus (which is a great pack). I never use the waist belt, nor do I want to with loads that are this light. Back when I was ignorant and carrying 50+ pounds, using the waist belt gave some relief (or enabled my entire body to suffer equally). Now that I am carrying nominal 25 pound loads I can whistle a tune and carry the pack all day without getting tangled up with a waist belt.
So, all I ask of my packing methodology is that I don't have jabby things jabbing me. I am not on some macho trip, just surprised that so many are enamored of waist belts, is this really so?