In general, with elixir you get all the benefits of Erlang, pattern matching, light weight processes, OTP etc. But you also get Native UTF-8 Strings and String Handling. A modern Standard Library around common things like Dicts, Lists, Strings, Files, IO etc and modern documentation for all of it. You also get compile-time macro's and protocols which help reduce boilerplate and lets you easily extend your code. You also get a build in dependency and task management tool (mix).
All of this while basically living in erlang. You can call erlang functions with a slightly different syntax, :erlang_module.function_name, and you can natively use erlang packages and files with mix(it checks for rebar/makefiles and makes educated guesses on how to build them, or you can configure it).
If you think its a benefit of Erlang its probably also a benefit to Elixir.
EDIT: I also forgot you get things like the threading macro(|> from clojure et al), built in testing framework, and a VERY active and helpful community on irc #elixir-lang and the mailing list.
All of this while basically living in erlang. You can call erlang functions with a slightly different syntax, :erlang_module.function_name, and you can natively use erlang packages and files with mix(it checks for rebar/makefiles and makes educated guesses on how to build them, or you can configure it).
If you think its a benefit of Erlang its probably also a benefit to Elixir.
EDIT: I also forgot you get things like the threading macro(|> from clojure et al), built in testing framework, and a VERY active and helpful community on irc #elixir-lang and the mailing list.