I think the closer you hew to the original Ericsson use, the more certain you are that it's going to be a great fit.

We used it as the command and control language for these: https://www.icare-world.com/us/product/icare-eidon/

* Semi-embedded system that's used as an appliance, not a computer.

* Runs in an environment where people mostly don't want to mess with it. Might be days between reboots; might get turned off every night.

* Has to be pretty deterministic in terms of memory usage, response times, and so on.

* Recovers from something going wrong by going to a known-good state.

We didn't actually use any of the distributed aspects of it, but it worked out great for the other stuff.

> which ones it's less good for?

Scripting, string munging, any sort of small task, anything which runs locally (unless it’s changed significantly erlang’s distribution story is the worst).