I don't have a specific use-case off-hand but I can imagine this being useful for a library that targets Kotlin/Native specifically.
For example if I'm adding Kotlin shared code a native iOS app that uses SomeFramework, I probably want to expose SomeFramework's types directly in my Kotlin API so the native Swift/Obj-C code doesn't need to convert things manually. If SomeFramework is commonly used, there might be some utility code (eg converters between coroutines and SomeFramework's async APIs) that I want to publish as a Kotlin library for use by other people using SomeFramework in Kotlin/Native. In that case I'd probably want the Kotlin library to expose SomeFramework's types.
That said, this particular situation may not be super common.