Running rust in wasm works really well. I feel like I'm the world's biggest cheerleader for it, but I was just amazed at how well it works. The one annoying thing is using web APIs through rust - you can do it with web-sys and js-sys, but it's rarely as ergonomic as it is in javascript. I usually end up writing wrapper libraries that make it easy, sometimes even easier than javascript (e.g. in rust I can use weblocks with RAII)
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...