This will take a while, but I'm looking forward to it.
It's probably another big step towards "Swift everywhere," without worrying about bridging to C.
I've been doing little but Swift since 2014, and really like the language. I'm still "on the fence" about SwiftUI, but that's mostly because of the level of support from Apple, and the [im]maturity of the system. This will help with that.
Yes, and it means Swift scripts and modules that don’t reference UIKit/AppKit/SwiftUI/Combine will run on Linux and possibly Windows with zero or little modification.
I‘m a little sad though that they didn’t start this endeavor years ago, because IMO Rust has already built so much momentum that it will win (for the popular, medium to long term definition of „winning“).
I don't particularly care, whether or not Swift ever leaves the Apple ecosystem (like ObjC). In that domain, Rust will never "win." I think that Rust is an awesome server language, though, and I'm glad to see it gain traction. I just hope that it doesn't get trashed by a bunch of junk dependencies, written in it.
I find using apps written, using hybrid systems, or PWAs, to be quite painful (on Apple devices -and that includes that awful JS TVOS system), so I am a big proponent of real native apps.
I think whoever „wins“, it would be necessary to have good interop at least. Currently, Rust devs are integrating core libs into native iOS apps by going the C route. All this work to make everything memory safe, and then this.