Yesterday I played a little bit with facebook ads & my PPC ads didn't get any impressions at the beginning as facebook has not yet collected enough performance data. So I though in order to speed up the process I pay for impressions instead of clicks. It worked pretty well and I quickly got a good relevance score. When I wanted to change it back to to pay per click instead of impressions, the estimated daily reach decreased by almost 1/3 although my daily budget has not changed. Pay Per Click at $10 Daily Ad Spend: 1300 - 4000 estimated daily reach Pay Per Impressions at $10 Daily Ad Spend: 7800-12000 Why is that? What is the benefit of paying for clicks instead of impressions if I get less impressions?