Not all web apps, but certainly a large fraction.
The use-case for this type of solution can occur in a relatively simple app (web app or native), with a master/detail layout when the user loads the 'detail' view for an item (and it has to fetch network data).
I'm looking at my desktop Spotify app and seeing places where this approach is applicable. Of course it loads so fast to me it seems unnecessary, but that will not be the case for everyone in the world.
Would probably be better to spend developer time on more aggressive preloading then.
If there are 30 items visible in the master view, and each is 1 kB of JSON, then just load the 30k of JSON in the background (after a delay, of course).
That should be considered regardless, it's not an either-or situation.
> If there are 30 items visible in the master view, and each is 1 kB of JSON, then just load the 30k of JSON in the background (after a delay, of course).
I said simple app, not completely trivial app! :)
.. whenever the fonts are loaded, the whole page changes, and I cannot longer keep a sane reference of what I was reading