He reuses (or rather, rehomes) too by finding buyers for cleaned and sharpened knifes of good quality. That's a plus from an environmental viewpoint.

I dislike scalping where no real value is added to the service provided beyond getting there first, but this guy uses his skills to pick out good knifes, does quality assurance and presumably sharpening, and sells them with the ability to inform buyers about the type of knife and its intended use.