Your point is fine. But the limitations on the iOS side are more significant than you seem to realise. things that I'm aware of that apps can take advantage of:

Your point is fine. But the limitations on the iOS side are more significant than you seem to realise. things that I'm aware of that apps can take advantage of: * midi signals * plain audio signals * looking like a usb flash drive to the built in photos app That's the whole list. The only one that seems vaguely useable for something like raw IO is midi signals!