In my opinion the best use case for blockchain, at least initially is the ability for unbanked people to have more financial power and freedom. This benefits blockchains like ours because of our abysmally low almost unexistence transaction fees.
Then comes the transparency and accessibility aspect in my opinion, helping create a more transparent society is always good.
Last but not least in my opinion is the ability to actually own digital assets with private keys and not depend on a third party, not only talking about tokens, that's just the beginning, we now have kitties, Steem Monsters cards and in the future who knows.
Building decentralized app
There should be streamline supply of chains