You know conquest exists too, right? It’s capped, has been since before crests even existed. And heraldry items to craft gear, which are bought with conquest. Conquest is limited. Each slot costs a particular multiplier and there is no way around it, and the stat value per currency spent is equal across all of them.
It does not matter if you get 1x of an upgrade out of a single dungeon run if the value of that one upgrade varies between amazing and actually worthless.