Earlier quoted context omitted.
> I guess you missed all those sites using Flash, Silverlight, Applets, WebStart, ClickOnce and many other plugins. I did actually, because most aren't around any more. Even so, I was talking about sites that purely use the html canvas to draw. There is nothing preventing websites from being built like that right now, so I don't see how webasm will make much of a difference.
You're missing it... Web Assembly would allow devs to build apps without any html or javascript or css. The UI construct could be WPF/XAML or even WinForms like tech or something new. Scripting and CSS would be entirely unnecessary. A lot of businesses would love nothing better than to dump the Jedi-like skills of the scripting developers and trade that for mundane forms skills.
HTML, javascript and CSS are easier than C, C++ or Rust. Writing a website in HTML/CSS/JS and updating a website in HTML/CSS/JS are vastly simpler than writing a graphical application then rewriting and recompiling it.
As with Flash, WebAssembly will be implemented as fully integrated apps where it makes business sense, which will probably be a limited number of cases, such as graphics or media delivery. Everywhere else, it will either not be implemented at all, or be used alongside JS in the existing web.