[OkayPhysicist]

I disagree. Any value could be nil, but any value could be 5, too. In fact, nil is just like any other atom. Elixir shines when you lean on pattern matching as much as possible. Your functions should unpack as much as possible within the function definition, frankly the "if" macro is completely superfluous to case and in rare cases cond. You'll find that you match the data you want, and thus reject anything else.

Square bracket dictionary accesses are a code smell, because you should be using %{^key = val} = dict or Map.fetch(map, key) or rarely Map.fetch!(map, key).

If you do that, managing typing in Elixir just boils down to defining structs to differentiate cases where dictionary A and dictionary B contain similar keys but strictly are not interchangeable.

[bPspGiJT8Y]

Any errors these techniques could catch would have to happen during runtime, not at compile time, and this is a huge and key difference. In my experience having the type errors being caught at compile time is an incredible boost to productivity. I just write code then hit Ctrl+S and the compiler tells me what I got wrong, instead of all the hassle of having to write functions a line at a time, flip to IEx, run, inspect some intermediary value to make sure it works as intended, while trying to keep so many things in my head at once, which at times can be just overwhelming and highly frustrating.