I haven't, but the creator of the library (Brooklyn Zelenka / @expede) has given a few excellent talks that reference her libraries. This is a personal favourite: https://www.youtube.com/watch?v=JD0FJTmuV_Q
I've used protocols, and they are useful as a kind of bare minimum interface/implementation abstraction. But they're nowhere even close to something like Rust traits. Which is totally fine given Elixir's goals.
[0] https://github.com/witchcrafters/type_class