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 :-)