The Vintage Icon Fretless Bass is meant to be fretless but I can see frets in the picture. Is that a mistake?

It's no mistake...those frets are painted on to the fingerboard! There are no real frets on this bass, it is truly fretless. Those painted frets are merely there to act as guides for your eyes and fingers.

What type of music is good to play on the Vintage Icon fretless bass?

That's really up to you because there are no rules! However, historically, Jazz and Fusion are two genres that mesh well with fretless bass playing. Fans of Jaco Pastorius will find lots to like with this particular bass...