This article applies only to Google Ads accounts in the new Search Ads 360.
When assets (formerly, "extensions") show, an ad is more prominent and, typically, performs better—more people click on it. There is no cost to add assets to your campaign. However, adding assets to your campaign may impact your actual cost-per-click (CPC).
Read more about how assets might impact your actual cost-per-click (CPC) in the Google Ads Help Center.