I could see that being useful if implemented in a framework - I'd like to see it perform some simple optimizations that most people don't like to do themselves (for some reason) such as looking for rules like border-radius and automatically generating -moz, -khtml and -webkit versions. Shortening color values from #ffffff to #fff or #cc0000 to #c00 would be cool, same with box model settings, margin: 15px 10px 10px 10px to margin: 15px 10px 10px and so on and so forth.