What does it mean to think that nothing is useful and everything is useful?

If you think the stone drum is useless, it is worthless. If you think it is useful, it is the ancestor of all kinds of treasures.

Although the seal script on the stone drum was later than that in Oracle Bone Inscriptions, it was much earlier than that in Qin Zhuan.

It seems to be talking about the relationship between commodity value and practical value. Ancient classical Chinese is polysemy, but Su Zhe's poems are profound and profound, and the meaning can't be explained clearly in a few words. So I want to provide you with a thinking path.