I don't get your example? You cite one use of the iPad and compared it to my statement. So this means I'm looking at it too narrowly? Elaborate please?
To elaborate: Yes, Amazon Cloud Drive can act like iTunes, insofar as you buy tracks from Amazon and can play them thru a browser via the MP3 player. No question Amazon will, like Apple & iTunes, expand this ability by using this "cloud drive" as the focal point for an assortment of applications, now that Amazon is in the e-book, e-movie, e-music, etc. business. I expect the Kindle will start using this in both overt and covert fashion. As Amazon observes what people use their "cloud drive" for, they will provide matching services to enhance and lock-in use thereof. The intent is to make this a disruptive product: its full potential may be unclear, but it's the groundwork for new ways of doing things - and new ways for Amazon to make money.
You're coming from a 'what it could be' which is at best guess in your own words, unclear. Right now they are using music as a beach head into the market. In future it could be something video or word processing related.
Is that what you're trying to say?