We just got back from WDW and we had the 3 bedroom grand villa at SSR. DDP was going to cost us way too much money since my 10 yo had just turned 10 only the week before we arrived - causing us to have to buy him an adult plan, even though his appetite is more in line with a 9 yo. Same thing with my 3 yo.
Anyway. To save money, we had breakfast foods delivered - milk, eggs, butter, bread, peanut butter, jelly and OJ. We brought our own generic cereals, the kind you buy in a bag. (that gave us more room in the luggage at the end of the week.) We had 9 people total and the grown ups mostly ate eggs and toast for breakfast and the kids ate cereal. We brought in our own granola bars for snacks, too, as well as empty water bottles which we refilled all week, then tossed at the airport. Our TOTAL grocery bill for breakfast foods for 9 people was just over $30. For the whole week. The DDP would have cost us at least $40 a day just for the adults for breakfast. We were there 6 days, that's $240 each. And that's not even factoring in the two 10 year olds (who must purchase an adult DDP) and the 3 other children.
Another advantage to eating breakfast in the room is that everyone eats when they are ready. Mom or Dad still in the shower but kids are up and ready to go? No problem, they get themselves breakfast. Dad hogging up the sink while shaving? Mom gets breakfast then returns to dry her hair when dad is done.
We ate all our lunches in the park, mostly because we have a sad history of squashed sandwiches at the bottom of the backpack.
We ate dinner in our room twice. Once we ordered in pizza. Three large pizzas easily fed our group (remember though that we had a 3 year old) for less than one family was paying for counter service lunch. The same delivery company also offered Italian dinners for delivery at reasonable prices. So again, 9 people fed for $30 instead of about $72 for just the grown up adults and the 10 year old "adults".
Since we also brought in our own snacks, snack credits would not have been worth it.
The DDP would have cost my family $133 a day. Eating breakfast in our room, bringing in our own snacks (though we did buy Mickey bars, popcorn, cotton candy and frozen whatevers on occassion) meant we only spent about $90 a day in the parks. We could have done better if we'd had a couple less table service meals. And WAY better with more dinners in our villa.
As far as the dishes are concerned - there's a dishwasher! If everyone rinses their plate and loads it in when they are done, then no one person has to do all the work. Unloading takes 5 minutes. Get one of the kids to do it.