The Reality Mediator goes beyond merely functioning as a viewfinder to set the camera correctly because the human operator is completely in the loop (e.g. one will trip and fall if it is not set correctly, since one will not be able to see properly), so that it transcends being a mere compositional tool, toward allowing the camera to ``become'' the eye of the wearer.
The nature of Personal Imaging is such that the combination of camera, processor, and display results in a visual adaptation process, causing it to function as a true extension of the mind and body: after an extended period of time, it does not seem to the wearer to be an external entity. Images captured on WearCam have a certain expressive quality that arises from having the wearer be ``in the loop'' -- part of the complicated feedback process that synergizes both human and machine into a single unit.