This comment from Reddit sums it up pretty well: https://www.reddit.com/r/elixir/comments/3gd1n3/what_are_the...

I just discovered about HiPE as well, and I just gave it a try with a simple fibonacci module. Running fibonacci(40) went from 3.9s BEAM to 0.7s HiPE.

I know it's a silly test, but it's pretty sweet to witness such a massive difference out of the box. :)