I have to think you must never have considered the actual math.
We had free dining for our trip in late 2010.
We stayed at Pop, so our room for the seven nights (before taxes) cost $685. With the 25% offered discount, we would have saved
$171.25.
The quick service free dining for two adults and two children was worth a total for seven days/nights of
$587.72. (For the math challenged, that saved us more than $400 more than a room rate discount would have. Even if you assume you would never spend quite as much on food without the plan, it saved us significantly more than a room discount would have.)
On the dining plan, we were able to eat every single meal, have every single drink and snack, and still have credits left over for a bunch of extra "free" fudge and other treats to bring home. Unlike a room discount, it also added an element of fun to our vacation, because my kids knew they could each pick two special treats a day. They enjoyed figuring out which fun stuff they wanted to try.
I think those who poo poo the
Disney dining plan must stay at deluxe resorts. Those are the only resorts where a room discount
might be a better deal than the dining plan. Even then, it doesn't add anything to the vacation.