Sounds like you've never ridden in the mountains. Smaller rings are not for saving weight, they're for providing the gears you need for the terrain that you ride. Triple cranks used to be the popular way to get more low gears, but triples are just about dead, so now people use a 50/34 with up to a 34T sprocket, instead. I've been riding in Colorado since 2003. There are a lot of really steep hills and long mountain climbs. If I only rode flatter terrain, I wouldn't need the 50/34 crank.