The reason his system deemed the dual cultivation path most appropriate for him was the lack of spirit and other forms of energy in the region he was living in.
Of course, if he had been rich and had access to some other source of the energy, he knew the system would have chosen some other path for him. But since he had neither, the system chose the path that could help him.
Even though the system hadn't explicitly told him, he had realized this fact a while ago. After all, from the system name, it was clear it could refine any and all energy.
When Hannah told him about the white powder he was to use to activate the bathtub's heating formation, he became surprised and excited because he knew what this white powder was.
