Actors can be made to do structured concurrency as long as you allow actors to wait for responses from other actors, and implement hierarchy so if an actor dies , its children do as well. And that’s how I use them! So I have to say the OP is just ignorant of how actors are used in practice.

Except Akka in Java and for the entirety of Erlang and its children Elixir and Gleam. You obviously can scale those to multiple systems, but they provide a lot of benefit in local single process scenarios too imo.

Things like data pipelines, and games etc etc.