Play is activity that is useful and useless. It is useless because something is useful when it is for the sake of something else, and play is useful for nothing, that it is, nothing other than itself — it is for itself.
(Wu; The Butterfly as Companion)
Wu's two-fold observation brings new clarity to our understanding of Zhuangzi's theme of the usefulness of the useless. To be useful is to exist for something else. But to be for something else is to have "something to depend on." If, for example, we have as our purpose in life to make the world a better place, then our value is contingent upon our usefulness. (This sentiment is expressed in a wall-hanging, purportedly a quote from the Dalai Lama, which adorns a bathroom wall here on the ranch, and one which never ceases to make me cringe.) Our value thus depends on our fulfilling a particular purpose.
To this Zhuangzi replies that this and every other supposed 'purpose' are bonds and fetters. "But what if," he asks, "we depended on nothing?" He answers that then we would be free to wander free and unfettered. This is play. This is a celebration of life, or rather, life celebrating itself. Zhuangzi's vision is of life celebrated playfully — playful in joy and in sorrow, playful in responsibility and indifference. Zhuangzian uselessness has nothing to do with an absence of practical outcomes in the world, and everything to do with a free and joyful transcendence out of which practical outcomes naturally arise.
Wu's second observation is that play is useful for itself. It is its own reward. This is true enough. However, I think he might easily apply to this comment something that he frequently applies to others: "But Chuang Tzu goes further. . . ." Play is for itself in that it really is for nothing, not even itself. It is non-intentional; it is without ulterior motive. It is, as Wu suggests, "self-forgetting". True non-dependence, Zhuangzi tells us, does not even depend on furthering the goals of self. Play is uselessfulness — it transcends both usefulness and uselessness.
When Zhuangzi suggests his friend, Hui Shih, plant his useless tree in the land of nothing, where usefulness has no meaning, he is, of course, recommending the same for Hui who can thereby do nothing prescribed and everything he wishes beside it. There, like his tree, he can discover that his value is inseparable from his existence. He is 'right' because he is.
You can check out Scott's writings on Zhuangzi here.