This doesn't look like it has anything to do with the Unionpay agreement. Today you go and purchase an ITunes gift card at your local retailer by credit card and then use it to top up your ITunes accounts. Tomorrow you bypass the retailer and top up your ITunes accounts with your credit card directly. Big deal. You can still only use your ITunes account for the same purpose. Apple is saving themselves the costs of a 3rd party gift card distribution