Don't know why its not working for you .. coz I have tested it on Chrome 5.0.375.29 beta on (Mac OS and Windows), animation works very well on both one.
yes it is done as an experiment but don't you think by using CSS3 ... you don’t have to regenerate images every time you change the text, pages will load much faster because you don’t have to download separate images .
i can say by css3 in some portion we can replace the images.
CSS-Sprite is one way to speed up the load time but even though this css file is still much smaller than the size of images used in CSS-Sprite.
And on the other hand the programmer could change icon property(like gradient , radius etc) very easily.