As much as I love Disney Dollars, I found I really really liked the DisneyWorld giftcards more.
I could use it just like DDs, but I didn't have to bother with getting change. Swipe, you're done. Just like room charging, but it's immediate, no having to go back and check your statements later on like room charging.
We ended up converting our DDs to a Giftcard, and using the gift card instead. It was nice not to have to carry around bundles of cash and the gift cards are reloadable so it was easy to keep track of spending too.