Neighborhoods go through booms and busts of school age kids. These are actually a great solution to get through the boom, then you move them to the next booming neighborhood. Though the schools should be designed so they butt up against the main building and you can go down a hallway into them.

One school I went to has like a third the school with them, but they were down a hallway connected to the school. I didn’t even realize they were portables until years later.