Students who attend a mini-school benefit from spending time with other adults. They may learn things that their parents can't teach them. They are exposed to rules and values that differ from their own. They meet other children. They learn to participate in a group.
Parents enjoy several advantages when their children participate in a mini-school.
They can avoid homeschool burnout and enjoy a change of pace. They may pursue personal interests. Some parents use that time for focused attention for another child. If their own children participate, the family benefits twice. Teachers with a passion for a field can share that passion with others.