because hackers like to do things with less work. creating images means work. the code does look long though. it should probably be abstracted into a server-side view helper function.
Less work in this case = horrible results. You're ruining the semantics of the DOM to use a crappy method for creating rounded corners. Want to create a fluid box with rounded corners and even less work? Use Javascript. You're not writing crappy HTML and it's even less work; just tag the <div /> with a class.
If the quality of the implementation weren't bad enough, this method isn't even new.
