> 3. You don't need to use async Rust.

Technically correct, but… Want to build a web app, every more or less popular framework is async. Want to make a web request? High change of async. Database? Very likely async, too. A huge fraction of crates are async. Right now crates.io says there are "54172 reverse dependencies of tokio”. And the page that lists them struggles mightily to load. And that’s only direct dependencies of tokio, no indirect ones, no dependencies on other runtimes, no generic dependents.

And all the popular ones include a synchronous interface you can use instead of the async one. If if they don't, you can wrap your calls in spawn_blocking.

You might complain about it pulling in tokio, but that's a very different complaint than having to learn/use async.

> Want to build a web app, every more or less popular framework is async.

I think its the same as Java, Tomcat has some async threadpool inside, they just hide it from you, and your favorite rust framework doesn't, you need manually move your sync logic to Tokio spawn_blocking