So we have a box, we don't know why is here? All we know is that it came during some event long long time ago. Why do the NPC's even drop them? Any good idea's?

It is rare, just not that rare.  I think Othinn never finds them because he makes a habit of not killing anything.

So it's just a prop then... no function other than a small value.

I've been here since pre-launch and I don't think I've ever gotten one... maybe one once, but I might be imagining it. I probably recycled or sold it because it had no function.

Has anyone checked to see if the prop vendors stock them?

They didnt appear during game or handed out for any particular or mentioned reason (atleast not in my time here). They've always been there and are, for the selling price of them, stupidly rare.

I am nearly sure (as most have mentioned) that they drop generally in lower levels. if im correct i'd guess they're purpose was to balance reward for higher levels missioning with lower level mobs. I.E. a boost in $inf in the form of a sellable only item for money. Atleast it always dropped with lower mobs for me, hence my reasoning... (: