Why is creating three or more Search Ads per ad group a best practice?
An answer is “rotation”. When you have multiple ads in an ad group, Google will rotate them and show the best-performing one. According to Google recommendations, you should always have from 3 to 5 ad variations. Of course, It doesn’t mean that more than one ad could serve per auction. It means, Google will show an ad that will likely perform better according to various signals.