In the Origin World which didn't have any science or technology, it wasn't possible to replenish things which he had brought from Earth. All of dimensional space eyes were extremely advanced technological products, so each one destroyed meant there was one less he could possess.
Besides, from some angles, it could be said that the dimensional space eyes had even greater use in the Origin World.
Not only could they investigate and alert Li Yunmu of what's head, they were like the system's eyes and ears. After all, there was no online network in this world. Thus, the only way for the system to obtain information was to use the dimensional space eyes.
How formidable was the system's assistance? Extremely formidable. It could analyze and create a database from the gathered information. If the system couldn't gather information, then its ability to assist Li Yunmu would be weakened greatly.
