I think what irishjayhawk is trying to get at is that the OS that they put on the iPad essentially negates the ability to use any USB or SD input. Since it's running the iPhone OS instead of OS X. Nothing in the iPhone OS or any of it's current apps supports USB or SD input. If it's not part of the OS, that means no api controls for app developers to use to take advantage of it with 3rd party apps. So crippling it with the iPhone OS had the added benefit of making USB impossible to use with anything.
Which comes back to the bigger mistake of not putting OS X on the damn thing.
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