I think there might be killer apps that companies aren't publicizing, because it's part of their competitive advantage.

Example of WASM being used in a major product:

https://www.figma.com/blog/webassembly-cut-figmas-load-time-...

You can infer from this that it's making them 3x faster than anything a competitor can make, and probably inspired a lot of those 'Why is Figma so much more awesome than any comparable tool?' comments I remember reading on Twitter months back.