[deergomoo]

It's not XML though, it's HTML. HTML with additional nodes for layout, class names, etc.

If you're not invalidating the cached code multiple times per day (which, in fairness, a lot of the stuff from Google, Facebook, etc probably are), an SPA should use less data over time than a comparable server rendered app. The initial outlay is bigger, but once it's cached you only need the raw data as you navigate around.