i think cryptocurrencies as a whole are too young actually solve any issue in the world yet. but they all have a lot of potential if they get mature enough.
one of the best features is what OmegaStarScream mentioned above, and that is the cheapest transactions so far. anybody can send any amount they want to any person in any place of the world and as fast as possible while this is not possible with using current (fiat) methods. so cryptocurrencies can be a good solution for that.