I can't tell if you're downvoting because you saw the word "blockchain", or you really love it.
I'm using quotes in the title, because I suspect a major amount of people use the word "blockchain" loosely to refer to other related things. If you are willing to, please provide a definition of what you mean by "blockchain" as well.
Blockchain is touted as an immutable ledger of transactions visible to everyone.
The only proper use case I can see for it is audit logs where you never want to loose what transaction happened. That being said, we have existing technologies which provide this at a smaller footprint.