It would be reasonable to interpret the shorter boast as making the very surprising claim that it beats anything else, including lossy JPEG, in all categories of performance, including compression ratio. As it turns out, they don't intend to claim that, because it's not true. It's probably impossible for a lossless file format to do that, even for commonly occurring images. (It's certainly possible for a lossless image format to do that for images that have a lot of redundancy in a form that JPEG isn't sophisticated enough to recognize.)