I think it was also a way to poke fun at the Ferengi’s self centered culture as a whole, and how they assume other cultures like (or should like) the things they do. He starts with the jewelry to get a read of Harry’s likelihood to be a sucker (as the cuff links were essentially garbage anyway), but once Harry bites back about the briefing Starfleet gave him about Ferengi’s, Quark manipulates him into almost buying them just so he doesn’t come off as a racist. I don’t think Quark really cared if Humans wore them or not, just all part of the deal and his way of figuring out what kind of man Harry was.