'cos a USB HD wont plug into an iPad or an iPhone. And isn't usable if you make it plug in. iTunes or another 3rd party product is the only way to back it up. Apple doesn't just want you to buy iPads they want you to use them as the only window to your stuff. That they hold for you...good plan.
BTW, I just recieved my new OS4 netbook by courier today...
Ohh hang on.. that was a dream wasn't it....!
<<== Hang on Jean-Luc has been using the prototype for years..