Every modern desktop uses webviews in some capacity. macOS renders many apps with webviews, GNOME uses gjs to script half the desktop. The time to push back was 10-20 years ago, it's too late to revert now.
I don't think gjs is a webview. It uses JavaScript, granted, but binds to a native toolkit, not to DOM and CSS.
Meanwhile on Windows major features like the Start menu are written in React.
Worth noting that WebKit webviews also tend to be more lightweight than their Chromium brethren.