The primary function is on the paid app that an admin can monitor many devices (iphones, android devices, laptops, etc) from a single interface, and even get periodic reports that a device is still functioning properly and at a known location.

If the only device you own is an iPhone, there's probably not an advantage. If you've got several devices or are in a small company IT department with a mixed environment, it unifies them in a very nice way.

Because Find my iPhone is only meant to help you find your phone if misplaced, not stolen.

Law enforcement needs static, printable data in order to do their job, because evidence needs to be shown in court and Find my iPhone's information is only real-time, not historical.

Or heck, you can always do what this guy did:

http://preyproject.com/blog/2012/02/lost-found-case-v93l