[Philip-J-Fry]

If you've got 5 gen_servers and you cast each one a message then that is concurrency. The whole point of a gen_server is that it's a separate process doing it's own thing.

I can dump 1000s of things into its message queue and then do something else. It'll keep working away.

It's like saying threads aren't useful for concurrency because they can only do one thing at a time.

[nesarkvechnep]

I would advise to not rely on casting too much because it lacks backpressure.