I find it very strange that you see 'web development' as something that's bad, and the answer to it is to write C and ship assembly code to clients.
If we aren't being disingenuous, it's "any language you want versus JS" and "minified, obfuscated JS versus assembly".
That said, minified JS on the web runs in a sandbox with a sane security model (yes, browsers don't implement it 100% right, but at least there's a model there). Optimized native code without source does whatever it likes to any file on my single-user machine, and we're expected to be okay with that (cf. https://xkcd.com/1200/). If I'm asked to choose between running one of the two, my vote is with the web app, no question.
Is the security of WebAssembly worse than that currently? Or is it somewhat similar?