Glimmer is one of many things Bungie did not think through when they made Destiny. Currently, in-game currency consists of glimmer, Vanguard Marks, Crucible Marks, Strange Coins, and Motes of Light. That's 5 different types of currency. I know that at least 3 of these have a cap. And we wouldn't hit the glimmer cap if there were worthwhile things to buy with glimmer. (I spend my extra glimmer on engrams to rank up with the Cryptarch in hope of receiving an actually legendary from his legendary mail package).