Photographic clients buy photographs because:
1. It makes the buyer feel generous - supporting artists does that for us.
2. It makes the buyer feel smart - art is smart or so they say.
3. It makes the buyer feel like part of the creative process.
4. It is so useful there is no choice (such as wedding photo).
5. It benefits the buyer financially (because as a professional photographer you gave them an incentive to recommend you to friends.)
6. It makes the buyer feel happy.
7. The photographer is a very nice person and hard not to cheer for.
8. The work is better than anything else out there.
9. The work establishes an emotional connection.
10. The work tells a story that's important to the buyer.
11. The buyer wants to show off and having something pretty from a professional photographer to hang on the wall makes that possible.
12. The buyer is in awe of the photographer, the photo and the creative process and wants to share that with others.