redboxcar, that was basically our reasoning.
Made especially solid to us because we were ALREADY spending the money for
disney vacations. That money is going to vacations in one way or the other. Was it always going to Disney? Not always. But we were spending $$ on vacay.
So...send it to hotel rooms, or send it to DVC? Was a fairly simple choice, once we found out how EASY it is to send extra principal payments to pay it off years ahead of time, and how relatively low the monthly payment would be.
We have one small CC for DH's work trips (he has a corporate amex but many businesses do not take that card) that we pay immediately. We do have a car loan that was taken out of absolute desperation when DH's long paid for car suddenly and dramatically died and even HE didn't trust it anymore. Other than that, we don't do the interest thing. But with DVC, because we were already sending that money to vacation (aka hotels), paying some interest was palatable as a "convenience" fee.
Do I advise others to do it? I can't say I advise it. But I also can't demonize it. Travel to us is barely a luxury; DH and I thrive on it, it's hard to breathe after a few months of not going anywhere. We would be happy to buy a nice boat and just live on the sea, going where we want, if DH could get a job that would be happy with him doing that.

So for us, it's not really a luxury item. Big diamond ring? Luxury. Brand new BMW? Luxury. Travel? Not so much. So for us, in this case, based on what we were doing anyway...it worked. Not everyone has our particular circumstances, which is why I don't advise it, but I feel free to share our circumstances and experiences!