Actually, there's good reason for using something that slips on a finger. Aiming a camera at something you can't see with your head would be a lot of trouble. Exploring things by touch is much easier and more accurate. Take the price tag reader, how would you know if the tag it was reading was attached to the shirt you were considering without feel? It could be reading the price for a different product right next to it. Until we can read data straight into our visual cortexes, I think a smaller version of something like this will beat out geordi's visor.