It's quite a fun mechanic that isn't really used but in higher levels, or with expensive items, as belts, high level armours, or poly balls. Given that mining has few uses as well: Why not crafting level 30 weapons with a lot of minerals? Of course you could not get the rarity versions, for that you need to farm them.
Or maybe using minerals for the refine plus system for level 30 weapons, instead of the orc heart, maybe.