I my opinion web assembly is just increasing the usage of JavaScript.

I recently made this web app: https://www.minuteimage.com/

I use web assembly to run moz-jpeg and pngquant image optimizer. The website is developed using Vue.js (and thus JavaScript). Compression is achieved inside web-workers using emscripten (web assembly) modules.

So web-assembly made it possible to create a web site to compress images purely client side, instead of using a server side technology or a desktop application.

JS + wasm is really powerful: you can now do things that in the past required a native language. GIMP, today, would be a web app…