My employer has chosen it, and while it was fun to learn and is very neat, I don't think I'd ever write Elixir code for anything but a hobby project, especially if a large team is working on it.
1. Dialyzer is just a huge piece of shit. It's an incredibly impressive piece of shit, and makes it possible to pretend that Elixir supports typing, but it has so many edge cases that we've run into them writing even trivial code - and it misses a lot of things that, e.g., Java or Typescript would have no problems with.
2. Testing is kind of fiddly and annoying. It's very difficult to consistently mock things out. And yes, yes, it's a functional language so in theory every function should be small and trivially testable, but unless you're writing toy code, eventually you will have dependencies you would like to mock out in tests, and you will have complicated business logic living _somewhere_.