It seems to me that Coverflow replicates everything that is frustrating and unpleasant about looking for something in the real world. In stark contrast to the organised drill-down structure and instant searching of iTunes' library views, Coverflow brings you ordering on one axis and the need to flip through item-by-item.
At least, with Coverflow on the new iPods, you can go from start to finish in a continuous spin around the click-wheel. On the iPhone and iPod touch, it's an even more tedious and inaccurate flip-flip-flip action. Simply put: Coverflow, compared to the iTunes library, is the difference between searching the racks at a record store and walking into the store, saying the album name and having the CD magically fly into your hands.