No matter how large and self-sufficient a shelter you build in Fallout Shelter, it makes no sense without residents. Each room requires maintenance, emergency prevention, and resources, and all this requires workers. In addition, you won't even get access to some functions and buildings until you increase the number of residents. Of course, players can buy a pack of Mr. Handies and fill the floors with them, but this is unlikely to be better than dozens of people with high levels in different specializations.