Why design?
There are usability practitioners who completely dismiss the importance of aesthetics, often citing unattractive but popular websites such as Craigslist.
Aesthetics are not important if you have good usability
However, aesthetics do have a function. Attractive things work better. Studies show that emotions play an important role in the users’ experience. If a website has a pleasant visual design, users are more relaxed, tend to find the website more credible and easier to use.
A positive first impression — usually based on looks rather than interaction — determines the value of the website on the user’s behalf.