A well structured CV is even more effective if it is accompanied with a well concisely written "job specific" Advantages of having a well addressed Cover Letter as part of your Job Application:
It will support your CV; a cover letter is what prompts someone to open your CV.
It shows you have actually read the job specification and is not using a "shotgun" approach in looking for new employment. You are portrayed as the serious career professional you are.
You have the opportunity to highlight all the areas that makes you perfect for that position