I suppose you can write various algorithms in it, and have that code natively trsnspiled to different languages, for ease of native interoperability. It's unlikely to produce the absolutely most optimized code, but the lack of the interface translation barrier (aka FFI) may more than compensate for it.

Rust is not easy to target efficiently, due to the borrow checker, and they likely don't want to dyn Box everything.

I first thought you were going to ask about the usecases for the austrian fut lol