I think this is highly misleading. They state that they achieved high speed-ups from not doing any coordination because they encode each state as a "private fie

I think this is highly misleading. They state that they achieved high speed-ups from not doing any coordination because they encode each state as a "private field" in an actor. Actors then communicate via queues (assume ZeroMQ from their reference), which require coordination to scale at some point - so do the actors that contain the actual data. I do see some market for (eventual/in)-consistent databases though, so maybe that's something we are going to see much more often in the future.