Side effects free is a good thing? Sure. Easier to debug? Cmon, elixir MO is based on, if not copied from, ruby. If anything, elixir is as easy to debug as ruby, if you can claim such a thing (I don't have substantial XP)
That's flat out false. Only the syntax is taken from Ruby, that's it. Even the added metaprogramming isn't anything like Ruby's. It otherwise just like Erlang.
Other than that if you look at how the language works under the surface it is completely different from Ruby which uses Runtime Reflection to add methods to objects in memory.