Rust can be used in contexts like dynamic linkers, kernels, libc, microcontrollers, dynamic libraries, and all sorts of places go has no business running. And it can use async in many of them. Go works fine for many contexts but we already have languages like go that work for those contexts. Rust is for the contexts it doesn't work well for. It's painful that it keeps being pushed to support things that would make it more difficult to support the areas it is unique in supporting.