This encapsulated widget pattern provides basic jQuery functionality through Zepto without conflicting with other jQuery versions.
While this might not be the most beautiful solution in the world, you might run into a situation where you need to add widget (toolbar, window, etc) on a page/site on which you can't control/change the jQuery version. This could result in multiple versions of jQuery which is never a good idea
It solves this problem by adding Zepto (which provides most of jQuery's functions) which can be loaded safely without messing with the global $.
You could, but i've run into situations in which I couldn't be sure where the plugin would be loaded (before or after another jQuery version). This pattern enables you to include it anywhere in the page. Zepto is loaded dynamically.