[out_of_protocol]

> its differentiation from Elixir is purely syntactic.

Well, there's also standard library, Erlang one is very messy while Elixir one is very consistent (and pipe operator - `|>` - enforces order of arguments even in low-quality 3rd party code as well, making whole language more pleasant to work with. Same goes for utf8-binary string everywhere and other idiomatic conventions