Knowing your traffic data, can help you in many ways.
Morningscore's traffic-checker, shows you an estimate of your traffic. If that estimate is very low compared to the monthly searches for the keyword, you are looking at, then it can mean that there are room for improvement on that keyword.
On the other hand, if your estimated clicks are very close to the total searches, then it can mean, that you won't need to focus on that keyword currently.
You can also use the traffic-checker on websites, to see which websites give you the most traffic, so you know what pages will be seen by the most people.