Hey, I'm one of the devs. it's definitely more like git than a blockchain, but the use of the buzzword probably helped us get funding in the project's early days.
We've gotten the system to run over webRTC before, but didn't bother working on it further. Aside from the matter of ordering messages, most people also expect that their data will be stored somewhere when they edit a document, so it's hard to eliminate that part of centralization.