Anecdotally I've seen quite a few job postings recently mentioning Elixir. That it can be seen, along with Phoenix, as a more performant, easier to maintain successor to Ruby/Rails gives it some legs imo.
Beyond the superficial syntax similarities and the fact that Jose Valim was a major Rails contributor I really don't get this Elixir = Ruby++ thing. The languages are poles apart, based on opposing paradigms (FP vs OOP) and data structures (immutable maps/lists vs mutable objects).
It's more about Phoenix than Elixir alone. The language is approachable enough, although clearly different, and the frameworks are similar enough (router, controllers, templates, gem -> hex, etc.) that a rails dev can become productive in this environment relatively quickly. And, the effort to do so comes with a number of serious benefits.