I've done this a couple times to pay off my DVC dues and to pay for other trip expenses, but I think I'm done, having concluded that it's more hassle than it's worth. On our last trip I was trying to use GCs to pay for park tickets and the lady at the front desk kept running them and telling me there was no balance on them. I had saved all the activiation receipts so I knew eventually I could get it all worked out with Target when I got home, but at that moment I wasn't about to miss my vacation. So I was preparing to put the park tickets on my VISA when the lady realized she was running them the wrong way and had to back up and start over. I knew if I'd gotten stuck with the cards I could at least use them to pay off my DVC dues the following year, but for someone else in a different situation you could get stuck with a lot of money tied up in Disney GCs if there is a computer snafu. Plus it took FOREVER for the lady to run them all. My family just wanted to get to the parks, not spend an hour in the lobby trying to get the cards on the room.
We had a similar problem, NFCEagles. We were paying off our RO resort reservation with Disney Rewards cards (we had four because we have four different accounts) and it took an hour! Granted the whole time was not dealing with the cards (they also had our dates wrong and it took them time (or maybe a few tries) to get our park tickets on our KTTW cards as well), but it took a LONG time. We will continue to use the rewards cards, but I'm definitely budgeting in extra time for that now!