The God-killing Spear had been Minghe's most precious weapon throughout all these years because it could devour everything to enrich itself. That feature saved Minghe a lot of trouble. Refining Spiritual Treasures required a lot of materials, and higher-ranked treasures needed larger and more precious materials. It was a great obstacle for Minghe, who did not have a rich background.
If he was alone, it would not be such a problem. But Minghe had the Three Separations. The four of them made refining Spiritual Treasures much harder, and the World of Heaven and Earth was a material guzzler. Most of the resources that Minghe collected had nurtured the World of Heaven and Earth.