1) Forced vacations. My wife works tremendous hours all year long, and our thinking was that if we bought into DVC, it would force us to take vacations or we'd be wasting money. So far, that theory has worked!
2) Through our careers, my wife and I traveled a fair amount and lived in major metropolitan areas such as D.C. and L.A. Now, we've settled in small town that we love but want our daughter to experience trips outside our state and country while allowing ourselves a bit of luxury with nice accomodations. So far, THAT theory has worked, too.
3) We decided years ago that under most circumstances when we traveled, we would spend the extra money to have a suite at a hotel. We felt more relaxed, more rested, and less stressed. We enjoyed trips more when we had room to spread out. DVC offers that. We always get 2BRs even though there are only three of us.
So, it made sense to us to combine our requirement for roomy & upscale accomodations, our need to push us to go on vacation, and our desire to show our daughter a world beyond small town living into one package--Disney's Vacation Club.