One of the reasons that hiddenness is such an important aspect of the spiritual life is that it keeps us focused on God. In hiddenness we do not receive human acclamation, admiration, support, or encouragement. In hiddenness we have to go to God with our sorrows and joys and trust that God will give us what we most need.
In our society we are inclined to avoid hiddenness. We want to be seen and acknowledged. We want to be useful to others and influence the course of events. But as we become visible and popular, we quickly grow dependent on people and their responses and easily lose touch with God, the true source of our being. Hiddenness is the place of purification. In hiddenness we find our true selves.
For further reflection...
Unless the Lord had given me help, I would soon have dwelt in the silence of death. When I said, "My foot is slipping," your love, O Lord, supported me. When anxiety was great within me, your consolation brought joy to my soul. - Psalm 94: 17-19 (NIV)