Traditionally sales people rely on the product to do their selling for them. Unfortunately, in many cases, it's their company that causes this to happen. They bring the sales people in, they train them on all the features of the product and then the sales person goes out talking features to their customers. As Thomas Lovett from Harvard business said "No one buys the quarter inch drill, they buy the quarter inch hole."
Customer Centric sales people are able to relate product usage. But in order to do that they have to understand how their products would be used by specific buyers in specific situations. Unfortunately, most companies are teaching sales people all about the product, but they're not teaching the sales people how customers use the products.