Disabling javascript makes Chromium eat less memory and makes pages load faster. Also all sort of annoying popups, effects, ads and social tracking buttons do not work without it while page content is usually readable. That's why I have JS enabled only for trusted websites like Youtube and disabled everywhere else. It just makes browsing the web more comfortable.

It's sad that Chromium doesn't have a way to disable CSS on a per-domain basis (and browser extensions are potential backdoors so I'm not going to install them).