I think Alvaro's at the Unison conference was a pretty cool demonstration of what you can do with the style of algebraic effects (called "abilities" in unison)
He implements an erlang style actor system, and then by using different handlers for the algebraic effects, he can "run" the actor system, but also optionally make a live diagram of the actor communications.
https://www.youtube.com/watch?v=u5nWbXyrC8Y
He implements an erlang style actor system, and then by using different handlers for the algebraic effects, he can "run" the actor system, but also optionally make a live diagram of the actor communications.