Which altcoins have exclusive final use cases?

In other words which altcoins have a specific specific final use case associated with them that no other currencies can facilitate? Generic gambling games and anonymous payments are examples of use cases, but they aren't exactly exclusive as there's thousands of poker games on the net and many anonymous currencies.

Bitcrystals are a good example of an exclusive final use case. *No* other altcoins can be used for the game associated, and you are incentivized to pay into bitcrystals, unlike huntercoin where you goal is to mine huntercoin through a game, and dump the huntercoins later on an exchange. DOT also seems to have a final use case in that, *only* DOT can be used to brute force your coin onto cryptopia.

What other coins like bitcrystals have an exclusive final use case? It doesn't have to be about videogames. Gamecredits would have an exclusive final use case if there are going to be games that *only* gamecredits can be used to pay into... although I don't think that's the road they are following down....