Showing your ads on top of the mobile page in search results is beneficial because:

• ads below the results get more prominent notice with smaller mobile screens. There are also ads on the right–hand side of the results on mobile.
• ads above the results get more prominent notice with desktop screens. There are also no ads on the right–hand side of the results on mobile.
• ads above the results get more prominent notice with larger mobile screens. There are also no ads on the right–hand side of the results on mobile.
• ads above the results might get more prominent notice with smaller mobile screens. There are also no ads on the right–hand side of the results on mobile.