There is a difference. The advanced Scala one may be simpler in concept if the high level concepts/idioms are known and a complete mystery if not. With less expressive languages the complexity is due to the volume rather than nature of code if that makes it any clearer.

Metaprogramming or code generation is similar. You can certainly make smaller, more sophisticated solutions with it. I would consider that has a comprehensibility cost and need some justification for its use, if not merely for academic/learning purposes. Maintainability could go either way depending on the situation and team composition.