Content thieves consistently offer to give a link to keep the content. Why is that? The answer is because they're ranking with it. If they're ranking with it then that means they're getting traffic. With your content. That's traffic that you aren't receiving for the same content. Someone obtaining your traffic with your content is never a positive. ;)
If they are throwing you a link and taking down the content, then good onya. But consistently the deal is that content thieves offer a link in exchange for your traffic. Not a positive.