With ATF you could use DXT1 in webgl. But DXT1 may have some trouble with gradient if I remember correctly. So it depends of your images. But your image is directly uploaded in the GPU => faster and lighter!
With ATF you could use DXT1 in webgl. But DXT1 may have some trouble with gradient if I remember correctly. So it depends of your images. But your image is directly uploaded in the GPU => faster and lighter!