What has you burning CD/DVD every day?
I work at a professional live theatre production company, so I burn DVDs of TV commercials and video elements for shows, archives of artwork, music score CDs for cast members and many other things.
The needs of a desktop are different than that of a notebook. Many people prefer to carry around a lighter notebook but they still want battery life and a reasonable amount of connectivity.
For some the needs are different, but for professionals who need the power and portability of something like a MacBook Pro, they may often find themselves in need of an optical drive.