They’re not much better and more complete though, they’re completely different. This technique is basic, and really specific – to x-pixel wide borders – rather than rounded corners in general.

To address some of the previous points – much of the span / div scaffolding is necessary because of the current state of browser (as in IE) capabilities. Ideally we could use first-child, or multiple background images in the same box, but it just aint practical at the moment.