We have a large family and normally get 2 connecting rooms at a value resort and travel during
free dining weeks. We have priced out renting DVC points twice and we would need at least 2 bedroom villa and it does come close to our FD price. It's over $2000 more on an 8 day trip for us to rent points at DVC instead of applying a FD discount on 2 connecting value rooms.
If you are planning on staying at a deluxe resort and have a family of 4, you can get a cheaper deal renting points over a FD offer, but not by much and you still have to buy food.
Renting points is usually only a better option during higher crowd season when the discounts are few and far between, not during free dining weeks.