Let me give the other story. We took snacks. And we ate them. We had a 12 hour trip by the time all was said and done...you know, those numerous potty breaks that happen when you have kids?
We took some to the parks, and we ate them. And we brought some home. Cause we bought too much, but it was ok cause it will get eaten here as well.
We only bought 1 meal on our drive down, 1 on our drive up. We only bought 1 meal in the Parks. Eating meals in the park wasn't a big priority to us, we'd rather spend on our money on other things. And the odd Mickey bar we got at Epcot.
So if you want to save money, yes bring snacks. Things that worked for us, that kept us full so we didn't want to buy food in the parks was beef jerky and dried fruit, mango's in particullar. We also had trail mix to snack on. Thus satisfying the need for sweet and salty.
So, if you think you'll eat them, bring them. Just bring some quantities. Just because DIS'ers say not to bring them it's a waste, doesn't mean it's the Gospel Truth. If you're normally snackers, or if you just want to save money, then by all means bring the snacks.