I can't say I ever understood how and why async became such a big feature for Rust. I feel like I might understand someday (when I have more experience working with async code) but for now it kind of feels like adding it to the language was a massive, severe change which severely shaped the development and future of the language for years (async traits are still a work in progress!) and I just don't understand whether async was truly the right approach here, or the one feature to prioritize above all else.

As far as I know the community is (was?) still a bit divided on async, mainly because it's rough around the edges, and makes for bad compiler errors.

I wouldn't be surprised if 15+ years later people will think of async as "Probably great for its time, but there are better concurrency paradigms which we should shift to." similar to the shift from inheritance to composition.