Apart from the reasons mentioned above, Qiu Tu chose to honor the deal with Tang Feifei for another significant reason. That reason was that the region controlled by Xie Yue had very few Leyline Nodes.
Only 36.
It was the smallest region in the Boundless Heart Sea.
With such a small region, not only was the potential for power growth limited, but it was also easily susceptible to being taken over by others.
Therefore, if Tang Feifei didn't refine the Central Hub of the region quickly, it wouldn't be long before an Evil God set its sights on the unmanned area and came to refine it.
Offering it to Tang Feifei was certainly better than letting an Evil God benefit, right?
Moreover, the region controlled by Tang Feifei had 36 Leyline Nodes, while the region controlled by Qiu Tu had 81 Leyline Nodes.
Every additional Leyline Node significantly increased the time needed for refinement.