I've seen equipment that when you plug in an iPod/iPhone into the USB socket recognises the device and lets you choose from the list of content using the on screen menu system.
Does anyone know if the BA system supports this?
To the OP, did you try the USB connection using your device? I'm wondering if 'My Pictures' would also list the other content on your device?
One difference of course - using the RCA cable means anything that you can play on your device can display on your screen. Using the USB cable (if it is supported) can only play formats supported by the AVOD system.