Earlier quoted context omitted.
Do you have an example of this?
When Google Ads is linked to Google Analytics, the links append the 'gclid' query parameter to the URL they point to. This value is how a downstream conversion, collected by Analytics, is associated with the upstream ad click from Google Ads. The 'gclid' parameter is unique to the ad impression, i.e. it's a join key to both the term that was searched, and the user who searched for it.
(Disclosure: I work at Google, speaking only for myself)