Well, it's interesting accomplishment no doubt, but the CSS markup is littered with Webkit-specific commands. If the point of CSS is to achieve at least a modicum of platform-independence, isn't the purely academic?
Eric Meyer breaks it down very well:
But generally the CSS spec seems to be increasing faster than vendors implement it. Or rather every vendor is creating new extensions and pushing for them to go into the standard so their effort isn't just for fun, leading to the bloat.