It allows me to place apps that have long since been discontinued or banned from iTunes for one reason or another, back on my iPhone. For example, I don't know why Cycle Timer was long ago excluded from the iTunes store but I used to own it. Once deleted I lost the ability to ever download it back to my iPhone. Today I was able to. Another app is Easy Wi-Fi. Again this cool app was discontinued and not available in the app store and today I again downloaded it. Just a nice feature if you had apps you miss. You can now find them again in your personal app queue under iTunes >Quick Links >Purchased >Not in my Library. Enjoy!