Pure speculation on my part, but having it around 5 feet tall is presumably for the optical cameras to have a better view of the majority of adult human faces. If you're talking a remote control car (at least like the one I had as a kid), any camera is either going to get great photos of people's ankles & shins, up their noses if they're close, or lose detail because they'll have to be too far away to get a decent angle to look at a face.