There&#x27;s nothing particularly special about a one-legged Merkle tree though.  It was around before Bitcoin and it wasn&#x27;t widely used for much.  Without proof-of-work you don&#x27;t actually have a functioning distributed currency system.  What is the point of a blockchain without proof-of-work?  What problem does that solve in a uniquely good way?  Or are you just saying that banks are so far behind in technology in general that even this (i.e. cryptographically signed transactions) would be a big improvement?