Zhang Yi thought these techniques were very powerful at the time, but after several years he understood how difficult it would be to understand this technique that needed an advanced understanding of space laws.
Moreover, on the blue moon continent, this technique could almost be considered useless seeing that it was difficult even to find people who had an intermediate-level understanding of the laws of space.
But when attacking a large sect such a technique becomes essential, after all, even if members of the sect do not have a high-level understanding of space laws, several of them could escape the sect while Zhang Yi attacked.
In addition, usually large sects had special treasures that could use space laws to allow many sect members to escape, their sect an example in which several members could escape even under siege of three sects and poisons.]