Honestly, that mixing of concerns is the biggest benefit, at least for me.

While Erlang clearly lost the popularity war, using it (well, Elixir in my case) feels like going to an alternate timeline where it wasn’t a given that a good application used separately developed tools for frontend, backend, database, cache, service discovery, load balancing, containerization, orchestration, and so on. We really could have been on a platform that incorporated all of those things into a single runtime.

The way I explain Erlang to folks is: “it’s not a competitor to Python running Django in Gunicorn; it’s a competitor for Python+Django+Gunicorn in Docker on Kubernetes on Linux, talking via a service mesh and storing data in disk-persisted Redis.” In many ways, swapping out only the top of that stack with Erlang is going to leave you worse off than you were before.

Sadly, the Erlang renaissance was years late to the boom of containerization+orchestration+distributed systems, so we’ll never know how good (or bad) things could have been. Ah well, c’est la vie.