Altough I agree on one point, that the sliced up photoshop UI also can account for Cocoa. I don't think you read the whole article. The part about server side administration is that it's easy to edit and add functionality to your app in a snap without all resubmitting to the app store and apple hassle. I also point out that not all iPhone applications should be written like this, just for some apps the advantages of this method outweighs the advantages on using Cocoa (first-last sentence in the article).