>It's so much fun, but not that practical for scalable websites.

Git based kv has a bit different purpose than the regular kv storage. They are intended for communication between entities, running in parallel, sort of transactional memory. They are not intended for users' data storage.

That sounds more like a tuple space than a KV store?

Not sure, but the idea is that you could not only read and write, but write in parallel so the keys are merged according to the merge rule you've provided.