Scripting is better because Kotlin doesn't have simple dependency management like Grape and compilation speed is way faster than Kotlin's. One of Kotlin's downsides is compilation speed and kts (kotlin script) is even slower. Also, Groovy still has ton of utility methods in GDK not matched in kotlin stdlib.
Other than that, I'm sad to say, Groovy is dead or in process of dying. I'm seeing companies rewriting Grails apps to Spring Boot and switching to Kotlin dsl in Gradle. It's a shame really, such a fun language to program in.