I am a molecular genetics graduate student with some experience in Python and C++ programming (99% of my work is in the wet lab). Recently, I came across the Github pages of bioinformatics packages being built using newer languages like Rust, Go and Julia. I am curious about why there is no interest in doing the same with Swift considering that Swift can theoretically run on as many platforms as these other languages. From a beginner's perspective, Swift seems to be powerful and yet have a simpler syntax than Rust and Go without sacrificing much on execution speed. Please feel free to correct if I have made any incorrect statement in this post. Thank you.
Swift itself is a very young language and is actively evolving. For example, the developers are still working on ABI stability (compatibility across future Swift versions) and source stability (Swift 5 compiler may not support code written in Swift 3). It is a lot of work to develop and maintain some sort of a specialized ecosystem when the foundation is unstable.
Additionally, although Swift is relatively popular now, most of Swift usage is among iOS/macOS developers. Thus, I would guess its usage among bioinformaticians (or academia in general) is very low. Even though Objective-C is relatively old and popular, it was never big in the bioinformatics community. For the same reason, I don't expect Kotlin to be a big hit either. Another example is C#, which is mature and extremely popular in the real world, but did not make headway in the bioinformatics community.
P.S.: There was an earlier discussion here about some of these hot new languages if you are interested: Yet Another Programming Language