Q & A section in your detail page is very good opportunity to describe product features. It also reflect the attention to the product from other buyer as well as attention from seller to the customer.
Questions can be submitted by customers, whether they have purchased the product or not. Answers to these questions can be submitted by any customers (again, whether they have purchased the product or not) or by the seller itself.
If your product doesn’t have a questions asked you definitely must fix this. Engage your friends to ask question and then leave your answers. With your product growth new question and answers will be published without your intervention. But it’s a good rule to answer the question as a seller to show that seller remains on connection with buyers. So don’t hesitate to answer the question even if it was answered by other customer.