I'm pretty sure it's just supposed to be a token of their appreciation for the hard work you did by slaying Tchort and returning the Cube back to good hands. It has no functional use within the game outside of unlocking an extra slide in the ending reel, so I wouldn't worry about it.
I also recall someone mentioning on here that its some sort of Dark Souls reference or something, but I haven't played any of the Souls games, so I can't really help you much there.
Regardless, it's just a medallion.