For cultivation arts, the difference of a single tier would result in a great disparity in the overall might.
The Coiling Dragon Spear Art was a peerless-grade heaven-tier cultivation art. It was pretty good, but let alone comparing it to the Grand Universe Formless Divine Art, it was inferior even when compared to the non-combat-focused Immemorial Vairocana.
However, this didn't mean that this cultivation art wasn't worth learning.
There was a type of cultivator, like Xuanyuan Po, who needed to concentrate and just train in a single spear art. If they cultivated too many cultivation arts, it would disrupt their instincts.
When they fought against their enemies, they didn't care what cultivation arts their enemies were using. They would simply use their cultivation art and overwhelm everything with brute force.