The linked article points out that Datomic doesn't support branching from the past. It absolutely does support branching, and I've built entire test suites that way.
From a cursory glance, I'd say Datomic does exactly what the original parent article is discussing. It works great and it's super convenient.
That said, I’m adding xitdb to the list of tech to try out. Thank you for building it!
Oh, and thanks for linking to my article :-)