If the potential buyers of the skill books were not limited to the players in Fang Qi's shop, then the items were put on auction just for fun.
Of course, there might be another reason. The special and heated atmosphere of the auction house and the urging of the auctioneers might get the same group of buyers to offer higher prices than otherwise.
Fang Qi had come to the auction to experience the event and to see if there were things he needed such as Bone of a Master, Deep Ocean Black Iron, and Spiritual Marrow. He had gotten the Dragon Bone from Huangpu Tao, but the others…
If he were lucky enough to run into these things, he would certainly buy them. Otherwise, he wouldn't be able to hold the event, Battle of Sand City, even after the players had reached level 40 or 50. He wouldn't be a qualified shop owner if that happened.
After all, this was his job.