As part of determining the quality score for a keyword, the PPC platform spiders the landing page and determines the relevancy of the content, among other factors. A landing page with good on-page SEO optimization will tend to pull a better PPC quality score, because it has more relevant content.

So the answer is yes, SEO work does tend to positively impact PPC search campaign performance.

PPC platforms, like their counterparts the organic search engines, utilize spiders to crawl differently. But the process of evaluating pages is quite similar. The PPC platform will assessment includes: Does the landing page have the keyword? What is the keyword density? Where do the off-site links go and are they relevant? What is the alt tag on images and are they relevant? Is this content linked to? If we follow the internal links, what do they lead to and is it relevant?  What is the user experience likely to be on this page?

All of these factors impact how both search engines, and PPC platforms assess a web page.