I found it interesting that the article mentions actors much at all for the same reason.

It's pretty trivial to construct actors out of some other message passing system. The interesting design choices in doing so are mostly down to the semantics in A) message passing, and B) scheduling/triggering/mapping-onto-green-threads/etc.

And for part A, all the other choices in the first three segments of the article are still effectively the choices that you've got to contend with: copying vs immutablity (bonus, COW mode, but still) vs ownership semantics.

Or to come at it from the other way: actors are far more featureful than is appropriate to directly compare to mere message passing semantics choices, because actors generally have some concept of error handling as a result of their relationship to scheduling, and that puts them on a whole different field.