You do need it for the DDE. We waited until we were at WDW to get our AP's, then I called DDE and ordered the card. They had it ready for me to pick up at the front of Epcot at 4pm that day. Things to know though: DDE is only open M-F, and you can't pick up the card before 4 pm on the day you order it (and it had to be at Epcot if I remember correctly). So check to see if this works with your plans and days and then make your decision.