With a fashion design focus, contestants compete against each other with restrictions of time, materials and theme. Their designs are judged by a panel, and the lowest one (or more) are eliminated from the competition until a winner remains.
These are shows that require so little attention to plot details that you can enjoy them while distracted by a task, like cleaning. While these shows are entertaining (and sometimes trashy), it would arguably be a waste to spend your time sitting down to watch them.