Blimey there's a lot of rubbish being spouted about staying on resort at Disney.
It is undoubtedly more expensive staying at a Disney resort than a villa. Same as staying at any hotel would be more expensive than staying in a villa (especially taking into account luxury levels etc). Same in the uk - we can find a holiday let/serviced apartment for our family far cheaper than the equivalent rooms in a hotel.
However, the DDP is not particularly restrictive - what you see is what you get. the standard DDP (one counter service, one table service, one snack, plus refillable drinks cup good for the duration of your stay at resort refill stations) is pretty easy to work out.
you get all of the above per person, per night of your stay, usually loaded onto your room keycard. you do not have to use to use one of each credit each day, so could for eg do 3 table service meals one day, followed by 2 counter service and one snack the next. the credits are valid from checkin until midnight on the day you check out.
the food at Disney is anything but monotonous. yes, there are several burger/fries places, but there is anything and everything else available too. I have done several Disney holidays, and have only ever eaten a burger when I wanted to (not very often, tbh, although the ones I have had were delicious!). The children's menus (children are age 9 and under) are quite restrictive, imo, but there are ways around this. If using counter service, then there is no difference between a child credit and an adult credit, so you can order anything rather than being restricted to the children's menu. At table service, you can book buffet restaurants, so obviously the children could choose anything available, or family style, where the food is brought out on a huge platter, sharing-style. Or, there is always the option of sharing from your plate, as the meals can be quite large.
I really don't see how anyone would end up buying meals rather than use credits due to restrictions - there aren't really that many restrictions, and extras can always be added (rather than buying a whole separate meal).
One bonus we found of the DDP (we haven't always done the DDP, but are doing it next time, and would always do it if offered for free) was booking character meals - it saves waiting in lines in the parks to meet favourite characters, and a break from the heat and sun, especially with little children, can be really refreshing. We've found that taking a break to have a meal can mean we end up spending longer int eh parks, as we feel refreshed enough for another few hours.
Look around carefully for deals when trying to book on resort. We are going in a couple of months, and got a good deal, imo. We paid £7k for a family of 5, for flights, 2 weeks at OKW (2 bedroom villa, which is huuuuuge), DDP, and car hire. other than tips at table service meals, we technically do not have to spend a single penny, as it is all included, and the DDP is more than enough food to spread over the week(although we will, of course, end up with extras and souvenirs).
I'm not sure I would want to rely on Disney transport for the hwole holidy. we have always used a car by preference (although you end up parking a loooong way from the entrance, rather than being dropped off right next to it), as that suits us better.