Research shows that you are at least 3.3 times more likely to get a click if you have both organic and paid search results on a page (position 5 or better for both). Keywords that rank high organically are rewarded with a high quality score from Google, and that means you will pay less for the click on the paid keyword and it will get a higher ranking. The important thing is that you get the click instead of your competitor, not whether you pay for the click.