It is unusual to have both freedom and protection. Wild animals are free but not protected; domestic animals are protected but not free. Children also are protected but not free. Adults may have one or the other, depending on the country or the time in history. But to have both is rare. That is one reason why sandplay is so compelling.
What is the freedom? To do what one wants. In verbal therapy one is free to say what one wants. In sandplay therapy one is free to do what one wants within the frame of the tray. Doing is more the whole person than saying.
What is the protection? From exposure. From being punished or criticized for what one does, or being judged, or even from being evaluated. Also secrets are kept. It is safe to be oneself. One need not put on the mask.
Kay Bradway, Sandplay: Silent Workshop of the Psyche;