For me personally, the best use case of Blockchain technology is that it allows authors and other content creators to distribute their work and receive payments for it immeditaley :-)

From a wider point of view, I think smart contracts are a valuable asset, since they have countless cases of use, allowing one to do a lot of useful things on the blockchain transparently, securely and cheap.
Some examples:

• keeping track of ownership rights
• being able to own and control your own digital identity
• automating mortgage contracts
• cutting out the middlemen in real estate
• taking out the possibility of manipulation in elections
• eliminating fraud on gambling sites.
• providing transparent financial data recording
  ...

I could go on for a while :-)