As I understand it, the light up patch panels are really a small part of a larger physical management system. The system also tracks the MAC address of active equipment so that it can be located, port usage can be tracked, etc. From what I've read, I would agree that most of the benefits can also be achieved with good documentation. To make this worth the cost I think you would need to be a fairly large organization with a low tolerance for down time and a big need for security.