I'm not sure what my point is - it's just not an easy sell?
Personal, subjective conclusion: Scala is substantially more complicated to use and learn than Elixir (to achieve the same ends).
Personal, subjective remark: Scala is substantially more complicated than Haskell. It's just so big.
If you know Elixir and are confident using it, you'll understand its benefits and when best to use it. I work for a dev shop where we use Elixir for client work. Elixir is performant and you end up making the most out of your server resources. That would be great for clients who end up having huge traffic. But more important than performance, I find it easier to maintain Elixir code largely because it's a functional language. Lastly, I think Elixir's Lisp-inspired macros are a great way to write reusable libraries/modules.
In essence, I'm more productive with Elixir than I am with Ruby even though I used Ruby for much longer. I find it a more pleasant experience maintaining Elixir code than Ruby code.
Try Jane Street's Core. I hear it's a better situation.
> "highly-performant"
On one core. Erlang and Elixir will blow it away when employing more cores, naturally.
Though OCaml would probably perform similarly or better (for certain CPU-bound tasks) when running N processes to N cores. You'll need to bring your own IPC mechanism - this is probably the key BEAM value add.
> syntax and alternative MO are still a big sell > web engineering > it's just not an easy sell?
You sell based on productivity, performance, and correctness:
"By using this technology, you will have less bugs, which is cheaper and more productive in the long-term."
Granted, this is a very hard thing to prove, it has anecdotally been my experience with ML-derivatives.
I would choose Elixir over Ruby or Python if my service needed to high reliability or if it touched the network in any significant way. Ruby and Python suck at concurrency and are "fragile" when serving lots of connections. Clojure or Scala (seriously, no one is building a product in Racket...) would be appealing but the JVM brings its own set of headaches and even with bolt-on large-scale concurrency support the JVM languages are not significantly better at these problems.
Broadly recognized syntax? Elixir is much easier for people to read than either Clojure or Scala and is close enough to Ruby that Elixir is drawing over a lot of developers from that group.
I use Elixir because it is fun, it scales well and has high performance for the problems I am throwing at it, and it helps me develop solid and reliable solutions.