Why would anyone require their children to dress up? People, it seems to me, need to dress in a culturally and situationally appropriate way. Dressing up just for the sake of dressing up does not seem to me to meet those criteria. We need good reasons to dress, no matter how we dress. We may not consciously be aware of those reasons in daily life. However, for a question like this, making explicit the reasons for dressing, no matter how one dresses, is important. Without explicit discussion of the reasons for dressing one way or another, there can be no meaningful answers.