Blockchains are algorithms to create public, redundant, distributed, immutable transaction logs without a central authority or transaction processor. I've thought long, long and hard about what would benefit from this kind of algorithm and the only thing I can come up with is ownership of cryptographic keys, and the only use case I can come up with for wanting a distributed trustless public immutable ledger of the transfers of cryptographic keys -- is a cryptocurrency or other token-like scheme!

Otherwise it is a solution in search of a problem. Distributed and redundant, but with enormous inefficiency. Immutability is actually a drawback in many cases. Most proposed uses like inventory tracking or etc. are much better served with a centralized database.