The military have done some interesting studies on this. I just read one on shoes where they found for every extra pound on your feet equals 6 pounds on your back. My thought is if you reduce say 8 oz it works exponentially. So over the duration of a trip this could save the equivalent of many pounds of stress on your body. This in the long run makes your trip mileage increase as well as your enjoyment. Instead of stumbling into camp exhausted, you show up energetic, ready to dive into your surroundings etc....

Where I hike we almost always have a major climb like thousands of vertical feet so any way to make the climb a bit easier is welcome. I've whittled my base weight down to under 10 lbs and the funny thing is I'm way more comfortable than ever before.