For one to have succes in life, looks can actually be very important. Not only in your sexual/love-life, but also in your career, where first impressions can be very important to get a job. To get the entire picture of how intelligent a person is, you have to know them for a while, but looks can be imtimidating, so in fact looking good can dramatically improve your chances in the job market, as well as the way people treat and respect you. It's just the way human beings work. We always typically see someone before we speak to them the first time (unless it's on the phone), and human beings just use the "elevator look" where we, somewhat, judge people on their looks, their clothes, their facial expression etc.
So currently, i actually wouldn't mind trading a bit of my intelligence for a bit of better looking. But I'm only 23. Once i turn 40 i probably wouldn't.