I'm buying a product from your store, I might not ever set foot in here again. I certainly don't need your company to contact me for any reason, I don't need you building a profile on me, I don't need you telling ad networks who I am and what I bought.
Every now and then I get a pushy retail worker trying to convince me that I should just give my number or email or whatever and I usually make a note not to shop there anymore.