Performance, speed, loading duration, and handling! If using more than one on your page, you can watch the performance of your page going down. It's getting slow, laggy - just no fun to use, as all the resources get loaded over and over again. With our Javascript API these problems will be avoided. Also, the needed resources only get loaded once - no mather how many bookshelfs or magazines you create. Another thing is, that the bookshelfs and magazines resize themselves automatically within the HTML elements you place them in, which, on the other hand, will be resized by your CMS (or whatever you are using).