The PP just said they won't eat the food. I can't see
free dining as a good deal for people who don't eat the food. They could pay less getting a room discount and buying just what they WILL eat, especially with a TIW discount on the table service meals (and some counter service).
Besides, free dining is a maximum of 14 nights, so they couldn't get it for 15 nights (unless they're British, the British offer is for up to 21 nights). They'd have to make a separate reservation for the extra night.
I don't care if the free dining is a deal or not, I just won't use the dining plan. There are others who agree with me on that. I don't like the way it obligates you to order meals (entree/dessert only).