I do agree that it takes a lot of time and bandwidth, but for the user it should just be one click. The app can just be a service that is installed and runs on system startup in the background, so the user never has to even think about after they clicked that button in the UI the first time.

With that said you've actually done it and I haven't. But it seems like the type of thing that shouldn't be too hard. I suspect Apple will nail it with iTunes support.