Thanks for asking the question to me too!
I enjoy it as an artistic hobby, most of all. I like to capture the beauty in nature that my inner eye notices and to preserve it and share it. Another reason would be to preserve memories, like many people have already said. In this domain I take family photos and photos of events that I attend. Yet another reason might be because it affords me a way of personalizing the world, i.e. the world as seen from my viewpoint, my eye. This might serve to make my personal recollection of a place or of a moment a tangible thing. Otherwise it would have to reside solely in my memory. The latter might not be a bad thing, especially for those with great memories. But the former is an aid to the personal memory of a place or a moment. As we say, a picture is worth a thousand words.
By the way, I liked your 6th reason which is something that we rarely think about. It is something that needs foresight to realize and take photos of for the future. It provides us a reason beyond ourselves to pursue photography for.
On the negative side, I have noticed that taking photos often keeps you from enjoying the documented moment itself. Also, to get great photos you have to invest too much into it (like an expensive, heavy camera and expensive, heavy lenses, and big files to later archive), into the documentation of life rather than life itself, the moments of life themselves. As such, I sometimes try to get away from photography. I think it's not worth investing too much into the mere documentation of life (as opposed to life itself, the experience of the moment itself, especially since life is limited) as in having to carry heavy gear and multiple lenses about. (This is my personal, subjective viewpoint as an amateur). Because of that I have been looking for an all-in-one great compact camera that will allow me to take photos along my way, while still allowing me to enjoy the things I take photos of, and not weighing me down, not causing me to make taking photos the purpose of whatever else it is I am doing (i.e. enjoying a trip in nature, an event, etc).