It's for in-browser, security and portability, generally not worth it performance.

A lot of edge cases they'd rather run WASM then a JS or Python VM, it has nicer containerization characteristics. But even with those key cases - it's not necessarily a core, critical technology.

WASM is 'always on the horizon' as being important.

If we had in 2015 what we had today, there might have been a bit of a breakthrough.