that is what i don't get either: in the case of sealed product you basically paid 3-4 times the actual SINGLES price just to be the one who rips open the booster. Does not really make sense to me.
On the other hand, if you want to get your hands on a sealed booster for your collection, then that MIGHT command a premium for you. For example, I am very happy to have a sealed booster for each hunters block set and I will not open them ever. A sealed booster is as collectible as a normal card because of its wrapper design.