Someone with little technical knowledge who gives a review of a product or service would say this phrase.
They would feel as if they are handing
out good advice
to people; But in reality they dont have the experience or analytical
ability to give a detailed review.
John: "How is your new camera
Bill: "it does
exactly what it says on the tin"
John has no idea whether the camera is good or not. He just knows that it takes photos.
If Bill had more technical
knowledge, he would have given more useful information.