If you invest time learning Erlang everything around Elixir will make sense and it will be a pleasant experience not only to "write" but to test, debug and maintain as well. I would go through this slightly dated but gentle introduction before learning Elixir: https://learnyousomeerlang.com/content

Thinking in processes and knowing/using the GenServer abstraction is the core of Elixir programming.

So, one negative is that difficult to use without Erlang knowledge. Also some good libraries are Erlang only for compatibility/historical reasons.