This is one of those cases where terminology matters. A blockchain is just a content-addressed linked list (that is: the "pointer" to the next node is actually

This is one of those cases where terminology matters. A blockchain is just a content-addressed linked list (that is: the "pointer" to the next node is actually hash of the contents of the next node, then you have a big hashmap of hash -> node contents). A merkle tree is the same thing in tree form. Git uses the directed acyclic graph version of the same thing. This approach is perfect for this use case. The decentralized Nakamoto consensus proof of work stuff is unnecessary here.