Two words--portability and advancement.
In the event that you leave your present community and want a different job, different opportunities, your BSN is portable and promotes advancement. The US Military seeks only BSN prepared nurses; the BSN is required for admission into MSN programs (for midwifery, anesthesia, nurse practitioner); there are hospitals and markets where an ASN will not get you any middle management job and any administrative job. I firmly believe that the ASN will always get you any bedside nursing job you want; the question is, is that ALWAYS going to be what you want from your career. Yes, you may point out the middle managers and the small hospital administrators that do not have a BSN or MSN, but that delineates the limitations of the credential. They are limited to those markets.
Finally, it is darn hard to say as a young or beginning nurse that I will never want to do those other things--unless your crystal ball is better than mine, but the BSN ultimately offers better portability and advancement potential and I will grant you that not all nurses will value that feature. Don't knock it for those of us that do.
More and more, listening to these ADN/BSN discussions I am struck that the nursing education consumer is at least equally if not more effected by the popularity of the ADN programs, so prospective students THINK like a consumer when looking at nursing programs
. I won't deny the fact that some folks need and desire a door in, a way to become a nurse that is cost-effective, but for the career-seeking individual AT LEAST LOOK AT THE BSN. I believe, for the reasons above, that it is a better life-time value.