In most cases, Organic SEO and Click Ads reinforce each other. Contrary to what people assume, usually, click ads do not steal from organic clicks you'd get anyway.
This has been studied and stated before, a new study says the same thing. In fact ALL impressions contribute to site traffic and conversions.
This shouldn't be a surprise. It is part of the basic theory of marketing that it takes repetition for advertising to work. But hopefully this will be the last nail in the coffin of what is called "last click" analysis - meaning you ascribe ALL the cause of a click to the link the person actually clicked on.
It isn't true, and is why professional Internet Marketers do not usually analyze the cost effectiveness of click ads separately from other online (or even offline) advertising.
An accurate analysis of this kind of thing is based on measuring the marginal effect - meaning, how do running click ads affect the overall amount of new business generated, no matter from what source.