1. no JVM (Kotlin Native isn’t considered a stable thing, or is it?),
2. subjectively nicer language,
3. An optional non-GC runtime upcoming (already in there as beta), which is interesting for low-memory applications... which in the time of the Cloud is potentially any application. The more (AWS) lambda time you can get for free, the better, right?
4. Writing command line tools. Practically nobody is writing them on Kotlin. Everybody’s writing them on Rust, though, for some reason...
Disclaimer, full disclosure: I’ve only read about Kotlin, of course, not written a single line. It seems like an excellent language, and if I had to do JVM work, I’d have it as a top3 candidate for sure.