The same reason people collect stamps, or watch birds, or watch trains, or whatever. They like to learn, and they just find it interesting, and they like to sha

The same reason people collect stamps, or watch birds, or watch trains, or whatever. They like to learn, and they just find it interesting, and they like to share with others who do the same. No one will claim that this behavior has great utility beyond that, though certainly good hobbies are valuable ends in themselves. Also, I immediately noticed the site does not have a map and does not give addresses for these buildings.