It could also refer to the difference between living in someone's spare room, couch surfing, or living in a camper van vs having a home (rented or bought).
Children living with their parents don't own houses, but they aren't homeless either. Or adults for that matter. For a few years in college I lived in a spare room in my grandparent's house. I had no house of my own, but I certainly felt welcome and wasn't homeless by any means.