What good interop does Kotlin have better than Clojure in what concerns calling Java code?
And on the other direction is just as fun, try to call Kotlin co-routines from Java without having to write wrappers for it, or Kotlin code without putting @Jvm... annotations everywhere.
1. Clojure doesn't have as good interop as Kotlin.
2. For some heavy interop projects, it's simpler to write the thing Java.