What reason would Apple have for a microSim card? The physical size of the microSIM reader in the phone is the same as a real SIM reader so there isn't s apace savings reason. I only can guess it is a concession to AT&T. In a way it lets them hardware lock the device to AT&T for longer as AT&T will likely be the only ones coming out with microSIM cards for a while. Tmobile will later on, but for the short term, there won't be any unlocked iPhones in the US. Any other possible reasons?