Is the use of Google Adwords an advantage or a disadvantage for my SEO?
According to Google, there is no connection between their Adwords sponsored links service and the ranking of websites in the search engine.
Some SEO specialists report both positive and negative experiences on the use, starting or stopping of Google Adwords on the SEO of audited websites.
The only point on which we can observe a connection between Adwords bots and the classical search engines bots is a system called "Crawl Caching proxy". This architecture makes possible the optimization of the global functioning of Google's resources.
This topic being complicated, I invite you to make a specific research on this subject if you wish to know more about it.
I think that there is no direct connection between SEO performances and Adwords but there are indirect ones.
Adwords allows us to bring traffic to a website. The analysis of the users behavior may impact the SEO of a website.
In that respect, getting traffic allows us to send signals that Google can then analyze. If this analysis is positive, it may be possible to see our referencing evolve positively.
In the same vein, we can also imagine that a website that does not or no longer receive any traffic is certainly less interesting for the users.