#1 advantage: zoomable. It's essentially procedurally drawing in the browser without using SVG, which isn't as integrated with HTML.
There are a ton of uses for drawing with CSS; I had a big commercial project that was pulled off this way. Requirements were no Flash and no SVG. It's the live "fear gauge" on this page: http://www.marketpsychdata.com/ (Unlike this demo, it uses images, and is not pure CSS drawing).
There are a ton of uses for drawing with CSS; I had a big commercial project that was pulled off this way. Requirements were no Flash and no SVG. It's the live "fear gauge" on this page: http://www.marketpsychdata.com/ (Unlike this demo, it uses images, and is not pure CSS drawing).