One could argue that some of the "physical" attributes are indeed comparisons. What you really mean to say is that for you, they don't mean anything. For others, it's entirely possible that these physical capability mean all the difference in the world.
Even if the ad only showed one computer coming in red and the other in blue - it's a comparison. And for some - enough to make their purchase decision.
For sure. My original statement, upon which everything else I said hinged, was regarding the implicit difference between what you do to something and what you can do with it. This ad is all about the doing to and none about the doing with.
"You can turn it into a tablet" is very different from "Here are some things you can do with it as a tablet" and even more different again from "Here is why the things you can do with it as a tablet are better than the things you can with a MacBook Air as a laptop".