Like Vonkara, I have private lightboxes with links from the images in them, and every view of those lightboxes must have come from someone clicking on a link - there are many views, so certainly people do. How much it helps sales I can't tell of course, but it can't hurt.
I also use the links to "related images" method a lot; I have no way to evaluate how successful that is, but again, it can't hurt and with DeepMeta it's easy. My feeling is it's likely even better than a lightbox - after all, someone has already viewed one image, they must be interested in that subject.
It's another way you have to market your own images against the competition. If the best match puts one of your images at the top and others lower down, then if a buyer views the first one they get a chance to see the others too. It can only help.