My new goal in my artwork is to produce drawings that are photorealistic. Sometimes I have heard the question, why bother? I have seen paintings and digital art that could easily have been an actual photograph. So aside from being able to say, "yes, I did that," what is the purpose of it?
I can't speak for everyone, but to me, photorealistic drawing (or painting or whatever medium) is a chance to improve upon a photograph, especially the background. Animals are particularly difficult to photograph, so getting one in a good pose from a good angle doesn't mean you'll get a decent background. For example, I loved the photograph I took of the snow leopard. But it had an ugly cement wall in the background and a chain-link fence in the foreground. I think I made a good change when I just made the background black. Also, for my koala, I changed the species of tree to look more like an Australian eucalyptus tree (not sure what he was actually sitting in). Again, it was a boring zoo background that I modified to appear outside high in a tree.
Then, of course, you can create expressions and situations that look real but would be extremely difficult or impossible to photograph - something I hope I will be able to do given enough practice. Or, better yet, what about extinct species? How could one draw a mammoth from a photograph? Photorealism has its advantages, and more than just being able to say, "I did that."