Also another benefit of google_user_id vs Google's Ad Manager cookie is, it expires after 14 days. So after 14 days, you will get new google_user_id for same u

Also another benefit of google_user_id vs Google's Ad Manager cookie is, it expires after 14 days. So after 14 days, you will get new google_user_id for same user. So syncing between adtech companies does not have much value.