Not in Rust if you use something like Tokio.

I'm pretty sure this program has no concurrency even if you port it to Rust and use Tokio.

This particular one, yes. However, most programs are a bit more complicated than that. That and Async is mostly used for io operations. In which case, the value here is not from non-blocking operations but from freeing up the CPU while this operation finishes execution. You can think of that as another form of executing this program on a separate thread (since the CPU will be freed to do other tasks).

Doing a blocking read also frees your CPU to do other tasks!