Elixir have better syntax because it's familiar.

I did play around with Erlang a few time. I really love the comma and period. It really nest and group the function patterns together.

For Elixir you just have to put them near each other. The function are enclose in a do/end block. And you put those similar pattern function next to each other. I believe you can move those pattern function around.

Other than that I can't recall much else. Prolog syntax is foreign but I'll admit I can see myself learning Erlang pretty fast since the language isn't "big" compare to Java or Scala. Like wise Elixir is a small language too with added macro (I don't recall Erlang got this) feature. Elixir also have better tooling baked in (mix/hex, doc, lint, etc...).

Also the Erlang community sucks. This is my personal experience but I vividly recall attending a meetup. The group meetup have a discussion about Erlang's adoption and how to get better adoption. I told them Ruby got popular because RoR other wise people would have chose Python and call it a day. Erlang should really have a killer framework like a web framework. Everybody thought it was ridiculous.

And you know what? Elixir came along and so did Phoenix. Phoenix may not be the only thing that got Elixir popular, Elixir got toolings from the get go. Jose and those people are from the industry they know what was needed. They came from Ruby.