A blockchain with authoritative access has marginal use: it can reduce trust (but not realistically defend against economic attacks) - it certainly pales in comparison to the societal application of a network which is robust while allowing arbitrary participation in consensus.
People, skeptics included, get stuck on the word blockchain and build arguments stating that any data structure which is a cryptographic chain of hashes is the true subject of interest. Blockchain doesn't offer the compelling parts of "crypto" anymore than a care without an engine offers the ability to drive.
Economic (or game theoretic, if you like) defense against converging power is the primary draw. It is why technologically minded people so often don't truly grok it - because the cryptography is (important) implementation details. It is the incentives which emerges from those schemes that is primarily important.