What feature would a blockchain give them that they can't have now in a simpler way?
There are lots of ways to do it. One of them would be for Fuuture to publish the hash to literally anywhere.
Public + cryptographically verifiable + distributed + append-only still does not equal blockchain, as long as we're defining blockchain as something that was not invented before 2009.
The extra governance layer that makes it a blockchain is also not trivial.