What Cao Jinyu wanted was not just the Yun Family's inheritance of national treasure-like wealth, he naturally would not miss out on the collection and Minor Spiritual Realm.
Because the development of any power cannot do without money, and to transcend, one must possess the capital to do so.
What is the capital for a power to transcend? For example, an invincible powerhouse, ironclad clan territory, or an escape route in desperate times.
Being invincible is merely one generation's glory, the later victories and defeats entirely depend on the quality of one's fortune, not even the An Family Divine Dynasty, Heavenly Wang Clan, or Yuanzhou's Xu Family, these sacred grounds dare to guarantee that each generation has exceptional powerhouses, let alone other worldly sects.
So the Minor Spiritual Realm is an escape route, the potential last resort left behind.