Perhaps that was the witch's ability.
Yorko realized that the eldest son of Luoxi family had only heard that a witch would be auctioned, but he had neglected her ability. A dangerous and eccentric ability would obviously reduce a witch's value, as no one wanted to be killed. Whether witches were affiliated with demons or not, they were not commoners and it was very hazardous to buy them off.
But the ability of this witch sounded not formidable. Self-cure was not able to hurt people, instead, it met some curious people's needs, so the price would be unexpectedly high.
"Sir, don't you want to bid a price?" No.76 firstly took the initiative to ask.