Even in the current era, the slaughter technique they possess is still incredibly terrifying. It's important to realize that this was founded through comprehending the Heavenly Path, and even when Heaven and Earth advance, it remains unaffected, with its power continually rising.
Though now it might not match those supreme divine powers in level, in terms of compatibility, it is most suitable for their existence.
This kind of slaughter technique lacks the varied effects of modern divine powers, such as aiding in comprehension of the Heavenly Path and Laws. However, in pure destructive power, it is not inferior to supreme divine powers when wielded by them.
As for using supreme divine powers to comprehend the Laws, Zhu Jiuyin has no need for that, since the authority of Time in this world is almost entirely in his grasp, with no one able to challenge him.