Super heavy bags

ona quick trwal o fyoutube i saw a number of videos posted by poeple working on super heavy bags, i can't off hand remeber the weight of the bags but they were very big as big if not bigger as a heavy weight boxer.

now visually it looks impressive but as i was watching i was wondering if there was really any point in working in a bag of that size. Certainly in some instances the strikes that the guys were putting in were making the bag sway a mere couple of inches, which to be honest a stiff breeze would do the same.

on a bag that size if you can't affect it much i feel that it is the same as weight training with weights you can barely move. you fail to get the full range of motion and finish any movements, instead the techniques get 'jammed' and you run the risk of injuring your wrist unless you start pulling your punches which really is a wasted oppurntiunity when doing bag work

what are other thought on using super heavy bags?