Site visitors are more inquisitive than ever before. Product descriptions, specifications and even reviews can sometime leave the visitor with unanswered questions. To reduce cart-abandonment and users hovering over the buy now button, decrease their uncertainty of the product, you'll need Q&A on your site. Allowing visitors to see commonly answered questions, lessens the chances for them to go "google it". Keeping visitors on your site longer increases conversion rate. You've worked hard to get the traffic, why lose it to someone else who has the answer?