Commemorative Coin

[Krausus]

I turned mine in. It's unique/untradable with no way of getting this coin other than this quest, if there was something else to use it on I sincerely doubt they'd omit it until later without adding in another way to get the coin in case you did turn it in. Turning in a seemingly useless u/u inventory -1 item for 25k seals seems like the entire point of the item.

I agree with this, I'm guessing this is a way for SE to introduce the black market NPCs to folks that still don't know about them.

edit: or what Asiaine said