How much you learn is dependent on how willing you are to put yourself out there, even if only for a brief period of time. While I prefer to travel for longer periods of time, I certainly will not knock a two week trip through Europe. You can learn and experience a lot with the right attitude and outlook.
To attempt an analogy fitting for this forum, saying that it "does not teach you anything you couldn't have learned from a brochure" is like saying there is no sense in starting your own company when you could simply work for one that already exists. Creating a company is much different than working for a company. Much like being in a place is a lot different that reading a brochure about it. All the things that make creating a company a valuable experience are the same things that make traveling a valuable experience: all the little details, the hurdles, the hassles, taking a leap, getting there.
Treating the old application as the spec for the new one is usually not a good idea. Define the problem(s) the new application is trying to solve instead of trying to copy the behavior of the old application. This is important for both developers and users. (http://www.chadfowler.com/2006/12/28/software-as-spec)
I like tackling the tougher parts first as assumptions usually conflict with the real world and the design will change once you start building and testing.
I also had a less than ideal experience while playing with Unbox. During setup it asks for your username and password, but does not verify that they are valid. I mistyped one, and as a result it was unable to download the item I had purchased. This wouldn't be a big deal except that there is no way to change your username and password through the software. I finally figured that the only way to change them was to uninstall the software and then install it again. Unfortunately, the uninstaller is not smart enough to kill the Unbox process before attempting to uninstall, so it hangs indefinitely. I had to make sure Unbox was completely dead before the uninstall would work.
In short, it took much longer than it should have to purchase and watch a video. And all of my troubles could have been avoided with either a simple verification during setup, or an option to change the password somewhere in the software (this may be missing because of DRM restrictions).
The quality of the video was fine, and the download was reasonably fast. The user experience was terrible, as was the UI for the Unbox software.
My parents (smart, but not terribly computer savvy) can purchase and enjoy media via iTunes. They would not be able to use Unbox.