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.
