I will say that I have seen this trend and I will give you one person's opinion.
I have a 24lb plane that puts out 48lbs of thrust. My two NiCad packs weigh 18 oz or just over one lb. If I go to LiON packs and regulators, I can drop about 8 to 10 oz. Lets say it is 8 oz. I can greatly increase my flight time from 8 flights a charge to maybe 20-25 flights a charge. (Most for me in one day has been 9) The packs will cost me over $100 and require a special charger ($50). My packs now cost me $48 and I use my existing charger. In theory I will get up to 1000 charges per pack but historically I have only gotten about 125 charges and 600 flights on a pack. If this holds true for LiON then I should get only about 125 charges and 1200 flights on these packs since I will not need to charge them as often. In both cases, I don't see where the reduction of 1/2 lb is going to make over $100 difference in my enjoyment of the hobby.
I JUST DON"T GET IT!

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