One big real-life problem is the inability to SEE stuff, like when it's dark all around you. When that happens and you try to move around, there's a big chance that you could bump into stuff, like walls, or step on stuff, like the dog. And honestly, driving the car is out, altogether.
Light energy can really help us solve this big problem, by bouncing off of the things around us and into our eyes. When light does this, our brain can figure out pretty quick WHERE all the things are, in what direction and how far from us. In that way, we can navigate ourself around, and we are prevented from bumping into something or stepping on it unless we want to. The light gives us our choice back.