Not gonna lie, I don't see too much value in async, but that said, I can see where they (the Rust devs) are coming from. It was an oft requested feature, and it was in the pipeline for ages, leading to Rust dev burnout.
That said Rust team is working on making it fully usable, albeit the space of efficient, zero-cost abstraction closures that work with lifetimes is a set of one language - Rust.