Comment Re:There is no Airplay involved. (Score 1) 392
Probably because USB is slow.
USB 2.0 is 280 Mbit/s (35 MB/s)
USB 3.0 might be an alternative in the future, but it's fairly new. Then again, the USB 2.0 subsystem is used on iPhone 5, so the actual interface layer is lightning in order to allow it to be smaller.