I just found out today that they're used by crafters to make Green quality loot items if they're HQ'd.

They're as good as an HQ item of the equivalent ilvl to begin with, and if HQ'd, they're as good as a Green item of the same ilvl.

This isn't a huge big deal or anything, since all the ones I've seen were in leveling dungeons, but some of them are crafting pieces, and make very nice crafter gear while leveling up.

So yeah. If you see that 'useless' white item from a chest, don't toss it! A crafter will want it.

Wish the game had a tooltip or something about them, I didn't realize this for a solid month.