I got it. All it does is wipe your network settings and reruns phone activation. All your apps and data stay intact. Not sure their reason for doing it. Maybe to fix the issue where some people phones display Samsung instead of Virgin Mobile as carrier.
Doesn't hurt to do it but if your phone works then I see no reason to. You would have to be on stock rom or one of the roms based of stock for this to work. Custom roms based on AOSP are missing the needed components for this to work.