Elixir and Rust - learning Rust a necessary skill for people using Elixir?

Nah, the thing with Rust is that it’s a nice language and people are able to implement NIFs with it thanks to Rustler. And you need NIFs when you have already exhausted all the tools available in elixir/erlang or need to squeeze every bit of performance for a specific operation by working outside of the beam.

So don’t worry about it.