I was under the impression that this was useful only for GUI programming, but yes, that's a use case. I'm happy to know there are other legit use cases.
Oh yeah! Pub/sub is useful anywhere you have an N message producers and M message consumers (where both N and M are >= 0).
I mean, the way pretty much everyone does GUIs (with the central message pump that pulls external events off of a queue and changes UI state based on those messages) is an entirely reasonable way to think of all systems that use message passing to communicate -e.g. Elixir or Erlang- between loosely coupled parts of the system.
