I don't see any use case where you couldn't write your app in a garbage collected language.

Rust is great for command line apps, tooling and well systems programming but UI stuff? Sure can be done but it doesn't really play to Rust's strengths.

Tauri at least allows people to use their JS knowledge so it is a much easier sell.

Of course if you just enjoy writing Rust that is fair, just saying it doesn't make business sense for most people.