Well for one thing the buttons are scalable, unlike images. Also I imagine that the truckload of CSS still comes in way smaller than the required image(s). If

Well for one thing the buttons are scalable, unlike images. Also I imagine that the truckload of CSS still comes in way smaller than the required image(s). If someone's willing to take the time to figure it out, it is not wasted. If indeed it is more efficient to draw buttons this way than to use an image, it makes sense to do this.