If we are talking about the context of a compiler, I agree: you should compile pattern matching to decision trees (DAGs), by way of something like Pettersson's algorithm. In my comment, I specified "in an interpreter", as I think it's the natural way to implement an SML-like match construct in that context.

EDIT: Perhaps I am missing Elixir-specific context and I apologise if this is the case. It was the unification that made me click this post.