*Anyone who says they don't want a DVD-RW because "they wouldn't use it" is really not thinking very far forward. Aside from the obvious burning DVDs from iDVD/iMovie to share movies and photos with people, the shear usefulness of backing data up on DVD-R is worth the $2 it MIGHT cost them. Backing up purchased iTMS content, audio and video, photos from digital cameras, etc etc is so much easier when you can put 4gb+ on a single disc as compared to 800mb on a CD.
It sounds like you use your Macbook as a primary machine- many other people do not. My macbook is a second or third computer in the house and mostly an appliance and something used to check email on the road. I'd never think of trying to author a movie on the thing, when I have an iMac with a huge display.