The Coil basically already had that except it dropped shards to get the platinum. This game doesn't hand out loot quite as often as an arpg so I don't really see them doing weapons, but Onslaught could definitely have a loot goblin that drops those trophy currency.

Needs to be a glowing Vex Goblin just named Loot that runs around and you have to kill it quickly before it teleports away.