Lin Wu's additional trump card against the other ruler beasts was also these very gems. If he wanted the gems could be weaponized and detonated. The detonation would use up all the spirit qi that was present in the gem at that moment and if the imprint seal was still present on the servant beasts, even their beast cores would explode along with it.
Lin Wu had thought that this could be used as a sneak attack to be used when needed. He wondered if he should gather more servants like these and make them work for him. The prospects seemed to be quite good and one of the things that Lin Wu lacked the most, 'Information' could be obtained from them.
Not to mention that if he managed to gather a sufficient amount of them, he would be able to disguise himself into them and make it seem like he was part of them. Lin Wu was pretty sure that if other beasts saw him, at least in the case of the rulers, they would be suspicious of him.
