People think visually. If you appeal to their visual hotspots you are golden. Your ebook cover is the initial impression that your visitor gets when deciding whether or not to buy your ebook and is the first step in the ebook marketing process. If they don't like your ebook cover they won't read your sales literature and will hit the back button on their browser immediately. They are lost to you forever. On the other hand if they like your ebook cover design, they will look closer at what you are selling. It is now up to your sales copy and the rest of your ebook marketing sales process to suck them in and sell them your awesome ebook. Your ebook is the worm you put on your hook.