At the very bottom he describes the use case. Mobile apps optimize for battery life by preferring one big long request up front rather than lots of little ones as needed. But you only need the first 10% of the data to render the first screen of your app.
You might want to render the first screen of your app without any ajax call. That's the best thing to do. There is no reason why your app cant render with datas directly.
Here's one:
How about the fact in some cases waiting on the latency of a data lookup before rendering the page makes it feel much slower and more sluggish?
In the case mentioned above of map markers, if there's real latency involved in the lookup and you can render the page sans markers and then populate them a couple seconds later, isn't that a superior UI?
Yes, if you are building a simple, moderate or low traffic website/app, it's probably a better practice to render the page with the initial JSON needed. But a lot of the people here are working on products with millions of users -- or just tons of data -- and that changes the equation a bit.
