It's not truly a "DVC" VISA card, it's a Disney VISA card and they allowed/suggested/encouraged DVC members to have "DVC Member" embossed on the card along with our name. I think it was more of a marketing tactic to "sell" the card. It certainly cost nothing to add DVC to the card- there is no special card for DVC members.
While there may eventually be some DVC incentive to entice DVC Members to use the card, most current rewards are general Disney in nature and the FL resident's discount falls into that category. FL Residents already get significant discounts on rooms and cruises as well as other things.
IMO, offering cash reservation room incentives to DVC Members is not a way to improve usage for that segment of cardholders.
Perhaps there will be some future incentive that will appeal to DVC cardholders.
Further discussion of the Disney VISA card will best be served on the Budget Board, unless/until there is some offering specifically for DVC cardholders.
The Fl resident thing is also a PR move on Disney's part. Disney has over the year gotten some good financing and regulatory help from Florida. They want to keep the people happy so that continues.