Although the Primordial world's spiritual energy is becoming increasingly sparse, it continues to develop in an orderly manner. The most direct manifestation of this is the further refinement and formalization of various rules.
The establishment of the Twelve Chinese Zodiac signifies a completion of the temporal laws.
The first thing Nezha needed to tackle was the Twelve Chinese Zodiac World inhabited by the Twelve Divine Beasts.
In Nezha's understanding, opening a world requires brute strength, leaving the rest to miracles. After all, this was how Zhao Gongming had taught him in the past.
Though creating twelve small worlds is less challenging for Nezha compared to Zhao Gongming, his cultivation is vastly inferior to Zhao Gongming's.
After consulting his mentor, Nezha decided to go for it. The vessels for opening these worlds would be none other than the remaining twelve Ocean Stabilizing Divine Pearls.
These items were indeed fine magical treasures, though merely "fine."