How is it different from serial numbers found on any hardware on the planet?
Discussion
They do. Intel uses them to know about a chips warranty status for example.
Phones have IMEI, yet we all still use them. Operating systems initialize a unique number on every install, etc.
This one is on the outside. I don't know if it's also on the packaging, but the more exposed a serial number is, the easier it is to start tracking them.