I don't know if this is what they meant, but I assumed they were getting at the idea that a good recruiter will find you candidates who are better than they app

I don't know if this is what they meant, but I assumed they were getting at the idea that a good recruiter will find you candidates who are better than they appear on their CV (because they'll be cheaper relative to their ability), and it would also show they weren't just spamming for a match to the template.