It is your decision if you want spoiled potatoes or not, but I can think of someone who would be quietly concerned if you keep buying them.

[ Even if Lan Wangji can't speak to the veracity of Wei Wuxian's story, he would at least be concerned about Wei Wuxian getting multiple spoiled potatoes. At least, that's the feeling Shinobu gets when she seems them together from a distance and after talking to Lan Wangji once or twice. ]