Mostly I just like it better. But otherwise in my day-to-day off the top of my head:

Less “magic” (fewer macros that may change semantics, straightforward config handling), focus on declarativeness, no variable re-binding, more powerful test framework (common_test), seamless Dialyzer support, better logging framework for structured logging, simpler/minimal syntax, personal preferences for tooling (until recently, direct support for releases was lacking in Elixir), and force of habit.