I think this is just a work-around for the sloppiness of the web. If all the resources for a page were compiled into a single file and sent all at once, this wouldn't be necessary, but that'd be inefficient to for subsequent page requests.

The benefit of the web was that you didn't have a fat GUI locally. With the push to aggregate assets together and get the entire UI/logic into the client browser, cached, and read off of remote services, we're slowly making our way back to local GUI apps. This time, the browser is the OS (forgive the poor analogy).

What was old is new again.