&gt; Even if the system is limited to trusted parties and forgoes the whole mining incentive, there&#x27;s still a lot of value there.<p>If you take away proof-of-work, then it&#x27;s no longer a blockchain.  It&#x27;s just a unary Merkle tree, an idea which has been around for a long time.  You can&#x27;t surgically extract out the most fundamental and important part of a given idea and then call what remains the same thing.