Yes blockchains have value - open distributed ledgers is the 1st implementation solving the double-spend problem. This in itself is a major breakthrough and has already led to many changes in how we do things.
But currently blockchain is over-hyped and over-valued. Many use cases are still better done by closed private databases. A lot of the answers above sound good in theory but will not/would not last in practice due to inefficiencies and scaling problems, and simply there is no need for some blockchains to be open and distributed - i.e. Burger King has one, why? Who cares who owns Burger King tokens and how those coins are utilised.
Just because it can be done, doesn't mean it should, or by doing it, value is created. Just hype.
Cheers