I guess that just like people in the other 49 states have a hard time grasping what beer buying must be like in PA, that similarly for PA people who have not bought elsewhere, that things like this must seem very foreign. For delivery purposes to stores, 12 packs can come in those cardboard flats, but are normally bought individually by consumers. The whole thread probably doesn't make much sense in PA, but 12 packs can be very popular ways of buying beer everywhere else. It is convenient to bring to a house party for a couple of people or a generous person wanting to share, etc. Really popular format for the summer months. At one beer shop that I used to go to all of the time in Huntington Beach, it used the be the most popular quantity pack sold.