A big part of the difference it that in a typical web application in most other languages, you'll think of your system in two parts: web and background.

With an Elixir/Erlang you tend to think of the web as just one interface to the application itself. The idea of background jobs in those contexts somewhat goes out the window when you have an environment where spinning up millions of processes at the same time is the expectation and not a terrifying scaling scenario.

Think of responding to an incoming web request as just another job, essentially.

Because everything is just message passing and there is no global state, the restart just looks like a function call. The supervisor will start a new process calling the function with the arguments that were passed to it when it was created.

Here's an example that will try to explain things.

https://medium.com/@tylerpachal/let-it-crash-creating-an-exa...