It’s all about Social Proof, that’s the name of the game! Here are some studies that explains how the ratings can increase your products conversion rates:

• According to Google, 70% of Americans now say they look at product reviews before making a purchase.
• A CompUSA and iPerceptions study revealed that 63% of consumers indicate they are more likely to purchase from a site if it has product ratings and reviews.
• According to Harvard Business Review research, a 1-star increase in Yelp rating leads to 5-9% growth in sales.

Furthermore, once your SERP will include the ratings and your search incoming traffic will increase – your store will get more leads which means more potential customers.