Apple's Iphone 5 uses a nano SIM

One of the less publicised features of the Apple Iphone 5 is its use of a new, smaller nano SIM, which means that Iphone 5 buyers will need to get hold a new SIM card before they will be able to use the device.
New SIM card, new charger connector. Lots of things changing, lots of things meaning you have to get new stuff. Why not get rid of the SIM card altogether like the rumors said a year ago?