SwiftUI has an incremental compiler with interactive workflows.

Rust has an incremental compiler. And TMU SwiftUI’s live preview is essentially a very rough approximation of what the actual build would produce; it’s not a suitable replacement for a real build when developing a non-trivial UI.

The experiences still fails short of XCode or Playground, hence why Slint has its own scripting language.

Sure, I don't disagree. It's just not clear to me that developers actually index that heavily on hot reloading to begin with.