It's better than those. I can write an integraion test that leaves the vm via http request a comes back in and the http handler only views a shard of the shared state of the system associated with that particular test. That's a concurrent integration test. You can't really do that reliably without the BEAM.
Thanks to Elixirs macros, the code for this subsystem is about 75 lines of code and in order to use it in a group of tests it's a single "use" statement at the head of the test, and the hooks inside of the main part of the code are compiled to no-ops in prod.
I can't say much about tooling because I never really worked with Erlang, only some toy programs. Elixir's tooling seems to be on par with what I'm using for Ruby, JavaScript and Python.