Why Using Conversions Imported From Analytics to Google Ads Does Not Actually Make Sense – Search Engine Journal
It’s not Google Ads conversion tracking using Analytics code.
It’s data import from Google Analytics to Google Ads, and a given conversion is imported to Google Ads only if it is attributed to Google Ads in the last click model in Google Analytics.
Last click in Google Analytics actually means last non-direct click because a direct visit is not a click in Google Analytics terminology.
It means that if the Google Ads click is followed by, for example, a visit from Facebook and then the user converts, this conversion won’t be imported to Google Ads.