You can't download the entire internet. And loading a new web page every time you push a button is slow.
That said, what I meant is modern JS enabled moving into the web things that should have stayed local. It's literally two step backwards (moving software into "the cloud") and one step forward (giving back some responsiveness through AJAX).
While I generally agree with the sentiment of "do more by coding less", and minimalist user interfaces, there are plenty of cases where you throw a whole lot of functionality out the window by outright banning JS.