I build a slower version of something with the same idea 13-14 years ago in Flash for http://www.makeoversolutions.com which most of these makeup companies licensed back then.

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.