This has been done in many, many MMos, where you obtain different “currencies” (e.g. dungeon rewards, pvp tokens etc), these should not be taking up room in your bags, they are a currency used to buy stuff so should show as currently and not items.
God knows the larger bags are gold sinks really but even then, with non-collectable crafting items, the bags fill up pretty quickly…
Please please please make the currencies non-items and just have them show in another tab