That makes a lot of sense. I could definitely see this getting annoying with people piling up gems and changing the way they play pretty significantly. I'm sure after trying it out for a little bit I wouldn't want this in my game all the time. I guess maybe it could be fun as a mod just for fooling around from time to time, if it wouldn't be too hard to mod.
It's the same reason the flare gun doesn't do any useful damage. If it doubled as an actual gun, people would spend all their flares shooting stuff instead of putting up lights for the team.