How do the clicked products stats work?

They display the number of products in the app widget that were clicked on by your customers. 

Clicking on the products in the app widget redirects your customer to the product page. This can be done to see the product details. That product may be or may not be added to the cart from the product page and may be or may not be purchased later. 

Repetitions are not excluded, a product is counted as many times as it is clicked on. 

If you don't have many products clicked on, compared to the product viewed, you may consider changing the app design to make the products more attractive.