It hasn't been a big issue for me so far, but Kotlin often favours fast and compact where Scala favours generic and beautiful. For example, in Scala, nullable

It hasn't been a big issue for me so far, but Kotlin often favours fast and compact where Scala favours generic and beautiful. For example, in Scala, nullable references are just another monad object implemented in plain Scala, while in Kotlin they have a special syntax around Java's null pointer.