Regarding Elixir being a dynamic language, I've programmed in Java, C#, and other strongly typed languages as well as Ruby, Python, Elixir, and other dynamic languages since the mid 90s. Throughout my entire career, I cannot think of a single time when I've thought, "It would be so much nicer if this language was statically typed." It just hasn't ever been an issue for me.
If typing is something you really want to catch at compile time, and pattern-matching and guards aren't enough for you, you can always define Dialyzer specs and run Dialyzer during your build process. I'm currently working on an Elixir codebase that does this, but I've worked on others that don't, and I haven't seen much of a difference either way. Personally, I think strong typing is overrated.
Not to mention that for a decade and more, HN was full of "dynamic languages are the best! Who needs types! Dynamic FTW!" comments and articles. It wasn't fully accurate, and neither is the about-face to "Types FTW! Typing is the best thing ever!".
I have come to enjoy the more self-documenting nature of static typing (in PHP of all languages). Yesterday I worked on a legacy project with no typing, and to determine what was passed to an untyped method (with no documentation) required running the interactive debugger and inspecting what was passed in different scenarios...
Well I mean there are a class of bugs they help to catch but with pattern matching it really don't come up very often. Just don't match the values you don't want. Sure it's a runtime error but you'll catch them pretty fast and elixir is fault tolerant.
If typing is something you really want to catch at compile time, and pattern-matching and guards aren't enough for you, you can always define Dialyzer specs and run Dialyzer during your build process. I'm currently working on an Elixir codebase that does this, but I've worked on others that don't, and I haven't seen much of a difference either way. Personally, I think strong typing is overrated.