That&#x27;s because Kotlin puts the complexity in the language and Scala puts it in the libraries. A lot of things are just a rule of the language in Kotlin but they&#x27;re implemented in ordinary code in Scala. E.g. extension methods. Which means you can &quot;understand&quot; them quicker in Kotlin, but you can&#x27;t change how they work or use them to implement a new structure.