In my experience, when people say "blockchain" what they actually want is something closer to a Merkle tree like what Git uses for its commit hashes.

It's great to be able to say "here is the list of changes, and I can re-run them and come up with the same hash, so nothing was tampered with"

The "here is a random key that took a lot of work to find and when you add it to the hash chain we get X number of zeroes" part is really not that useful in most cases.