Photos can be used in many contexts and mediums. Filling the frame is not always the best use of a photograph. Sometimes taking a photo with negative space could be advantageous and heighten the impact, for example, a magazine where text can be written in the negative space.
I thought about this concept when I photographed a very handsome man’s hand in the park whilst sending an email (although he should not have been working during the weekend, hmmm!)
This is a link to some more ideas and information on negative space photography: