There's a few good reasons:
Originally Posted by HTF III
1) Expense. Cameras are simple and cheap to build or even purchase. Why the heck not?!
2) Creativity: the images are unique and provide a visual experience quite different from anything else
3) simplicity. Point, expose, develop and there you go! This, for me is the #1 reason. Photography is a weird skill because you can make it as simple or complex as you want. In my case, after years of getting into more complex processes and workflows, I wanted to go back to basics. It really makes you focus on subject and composition when you have nothing else to worry about.
Oh, and it's fun!