Why is that? Just buy a small body, auto flowering seed, some fresh soil and water it every couple days and wait. You won't have a gigantic harvest but that's basically all you have to do and you will have more weed than you know what to do with. When grown, cut it, hang it upside down and wait until it's dry.
Anonymity. My neighbors, my parents, my wife's parents, the parents of children that visit my child, everybody passing our balcony on the street, and essentially every visitor to our apartment would assume that we consume drugs regularly. This is something I could not have cared less about when I was in my early twenties and living in a building full of students. But it is not something you want to be associated with if you have children in kindergarten or school and if you have to face other parents or teachers from your neighborhood on a daily basis. If I would start to consume cannabis, I would prefer to do it in private.