I use WebAssembly for a few cross-platform plugins. E.g. An AR 3D rendering engine in C++ and OpenGL. With very little effort it is working in browser. No bespoke code, same business logic, etc. Saved a lot of time vs creating a new renderer for our web app.
For me it allows a suite of curated plugins which work cross-platform. The web experience is nearly just as nice as the native mobile and desktop experience. This in turn increases market growth as more of my clients prefer web vs downloading an app (which is a large blocker for my users). I also enjoy the code reuse, maintainability, etc, :)
This year Max Factor (via Holition Beauty tech) won a Webby award for in-browser AI and AR. This was used to scan a users face, analyse their features, advise them on what make up, etc, would suit them, after which the user can try it on. This would have been impossible without WebAssembly.
This tech is also used by another makeup brands beauty advisors (via WebRTC) to call a customer and in real-time advise them on their make up look, etc.
Is this tech necessary? Probably not, but it is a lot nicer than having to go to a store. Especially when we are all in lockdown :)
I moved on from that a decade ago but it was a neat project at the time.
But I deployed my first integration of WASM about a month ago for PaperlessPost.com. It is a custom h264 video decoder that renders into a canvas that manages timing relative to other graphics layers over this video. This code works around a series of bugs we've found with the built in video player. It went smoothly enough that we are looking into a few other hot spots in our code that could also be improved with WASM.
One avenue for WASM might be simply polyfilling the features that are not consistently implemented across browsers.
Ten years ago I did the same but in Java and JOGL (before Apple banned OpenGL graphics within Java Applets embedded within a webpage). Was used for AR Watch try on within https://www.watchwarehouse.com and Ebay. The pain of Flash and Applets still wake me up at night.
I'm also building something very similar but with the ability for custom codecs (https://www.v-nova.com/ is very good). Probably the same issues too! Could I know more about your solution?
I think WebAssembly is more used than it appears, just difficult to see/tell.
A few years ago I actually tried integrating AR via WebAssembly with Amazon. We couldn't get the approval due to poor performance on Amazon fire devices (which have low end hardware). It is a shame but it is what it is.
What is disappointing/annoying is - as a CTO - it is near impossible to hire someone with WebAssembly skills. It requires an extra curious Engineer with a passion for native and web. Training is always important for a team but when going down the WebAssembly route you need to extra focused and invest more than what a typical Engineer would be allocated (E.g. Increase training from 1 day a week to 2-3). I suppose this may put people off?