Usable currency in acts

I can't remember the last time i used currency without being scared, (i've never used chaos orbs in acts) i can't use a chaos orb on an item because there is a 10x times better item on the market for 1 chaos.

So, the point? we need untradeable currency, besides the normal currency, currencies that we can only use on items, not hoard to trade, only in acts where it matters.

I think it will be a small addition to the game but sometimes impactfull.