It's not unusable per-se, however being unable to take advantage of Rust's fearless concurrency and having to glue everything together with JavaScript severely restrict the usefulness.

May as well just use TypeScript and React at that point.

The dream is to be able to specify only a wasm file in an html script tag, have the tab consume under 1mb of memory and maximise the use of client hardware to produce a flawless user experience across all types of hardware.