Gaining practical knowledge in childhood is wonderful preparation for life as an adult. Knowing how to balance a checkbook, fill up a gas tank, build a treehouse and cook food properly are all skills that can be applied later in life. Classroom theory is nice, but practical applications are even better!
Although abstract knowledge is important for a child, practical knowledge is important, too. Kids need to learn street smarts. If a kids are too sheltered, they'll never learn to be independent. It's necessary to let kids make mistakes and learn from them, or they will never be able to take care of themselves.