I don't understand how iTunes functions analogously to an SD card.
What I am saying is Apple wants you to use iTunes to move data to your phone and would never allow us a SD card.
Just adding a ringtone has to be doen with iTunes, where other devices do not. This way Apple controls what you can put on your phone to a point.
Can you imagine Apple giving us a SD card so we do not have to buy the higher priced phones with more memory?
Just not going to happen.