Keyword selection not only determines traffic it also helps to create a more useful website. Features and benefits have been a staple of marketing since the word was coined. Selecting keywords that speak to the benefits or ‘symptoms’ of your offering will convert more visitors.
Visitors that use a search engine to find your site are actively looking for something. Your site will be worth more to those visitors if you actually describe what they are looking for using the same keywords they selected to find your site in the first place.
The following diagrams demonstrate the relationship between increased traffic and good keyword selection.
Here is another way to express this idea: