> Is it a good enough idea to sync MMO game clients and servers?

After 15 years in the trenches on this stuff, no I don’t think so. Some operations need a clearly defined order for correctness. For example, financial transactions or items moving between inventories. CRDTs don’t provide this.

CRDTs are great when it makes sense for a local peer to own changes. Like Git. I think automerge and friends would make for excellent tools for making virtual worlds. For example, the recent work to integrate automerge into the Godot game engine.