Kotlin's are stackless (as in emulated by the compiler), Java's are stackful (as in a chunk of stack is copied into the heap along with a program resume point)

This means Kotlin's functions can become colored [1] which is a problem.

This said, I'm fully expecting Kotlin to react and pass on this feature to the users. Maybe after figuring out how to deal with Android.

[1] https://journal.stuffwithstuff.com/2015/02/01/what-color-is-...