An Eat Free Card?

there is a new commercial for Progresso soups advertising several of their soups as being worth 0 points on the Weight Watchers system. Now, admittedly I don't know exactly how the system works, but I think you get a certain numbre of points per day that you can eat and you can 'spend' them however you want. I would assume that the points relate to calories as well as fat or sugar content. Now, what I don't understand is how anything besides ice can have 0 points. This soup has 60 calories per serving, which is great, but still a caloric intake. So how is that worth zero? I don't think people out there are going to be sitting around eating 10 cans of soup (1200 calories - a full days worth) and then thinking 'hey, I can still eat that cake and not go over my points' and ignoring the fact that they have now ingested 2500 calories that day, but still - I don't get how it can be worth nothing.