An interesting point Sontag brings up is that from the tourist perspective, photography provides an outlet for the anxieties produced by travel and being outside of our comfort zone when we are in a strange or new place. She calls it a "friendly imitation of work";
"...stop, take a photograph, and move on. The method especially appeals to people handicapped by a ruthless work ethic -- Germans, Japanese, and Americans." It is something that becomes robotic, almost imitating the 9-5 work routine most people endure throughout their daily lives. It's interesting that the same type of behavior that is helping a person relax while they are on vacation is the same kind of thing they are trying to escape by being on vacation. People feel guilty for not working, so they emulate it with some other routine that comforts them. Luckily, it happens to be photography. A good choice.