However, overall I can tell you for absolute certain: if you have JS partially disabled things break in non-obvious ways and I find myself playing whack-a-mole with allowing various domains to load javascript to get the page working.

I'm pretty certain you do also, because it's basically impossible to tell why certain damned sites are broken and the most obvious thing to do is just enable JS temporarily to see if it works at all.

This is especially annoying on some part of a site such as checkout- where reloading the page causes a form resubmission.