It does work well logically but performance is pretty bad. I had a nontrivial Rust project running on Cloudflare Workers, and CPU time very often clocked 10-60ms per request. This is >50x what the equivalent JS worker probably would've clocked. And in that environment you pay for CPU time...
The rust-js layer can be slow. But the actual rust code is much faster than the equivalent JS in my experience. My project would not be technically possible with javascript levels of performance
I did. I don't remember the specifics too well but a lot of it was cold starts. So just crunching the massive wasm binary was a big part of it. Otherwise it was the matchit library and js interop marshalling taking the rest of the time.
edit: and it cold started quite often. Even with sustained traffic from the same source it would cold start every few requests.
