The reason why Zhao Hai thought that the Tiger Seal wouldn't be of much use in the hands of other cultivators was that other cultivators couldn't possibly have space. Without space, you couldn't have a group of people following you around forever. If a sect leader had this golden seal, the Tiger Seal would only be useful when he was in the sect. If he left the sect and went beyond a certain distance, the Tiger Seal would be useless. Then the Tiger Seal would not be able to help him extract the power of the other people in the sect.
However, if it could only be used in the sect, that meant that he had to wait for others to attack his sect before he could use the Tiger Seal to counterattack. Then, he could only defend well and would not have much power to advance at all. If he really let others attack his sect, it was not quite possible to turn the tables with just the Tiger Seal.
