The point is that as games consoles such as the PSP and DS become more media focussed, devices that were previously media focussed (such as iPods) move in to gaming. Apple are advertising the gaming aspect of the IPT, and this move indicates that they are going to move even further in that direction and really push the gaming features of the IPT.
As it is right now, I would imagine the average IPT customer buys their device as an iPod/MID and treats the fact that it can play games as an additional feature. My interpretation is that Apple are moving to bring in a new type of customer in addition to them - the type of customer who is out to buy a gaming device, and treats the iPod and MID sides of the product as additional features.
I think there's a high probability they will succeed. AppStore sales figures suggest that it is an effective way of distributing games and can be highly profitable, and Apple have added new features in 3.0 to allow for episodic content - unlike any other mobile gaming platform. These factors should lead to strong publisher and developer support.
Nintendo were in a desperate state before the Wii and DS, and despite those products being phenomenal sellers, I worry about their long-term strategy. They haven't shown much competence in audio/video or digital distribution yet, whilst Apple have, and have shown competence in innovative control systems (which is Nintendo's philosophy). This could lead Apple's products having a competitive edge, despite Nintendo's established IP.