A fixed week studio in the first two weeks of Dec at Copper Creek is 118 points, or, 43 points more than the 75 points that you were considering.
Ok. So that's $7826 more for the purchase: $21,476 vs. $13,650. But that price difference gives you a whole lot.
First.
DVC changes you. You'll want to go to Disney more, not less. You asked about the possibility of renting out 75 points if you don't go enough. Oh, ye of little faith. In short order, you'll be asking how to transfer in, or otherwise beg, borrow and steal more points.
So, 118 points is still way too few points (we have 520 points and can't make them work without constantly being in borrow mode), but at least you'll be in the ballpark of having a USABLE contract, a contract with enough points to make some things work.
A fixed week for the 1st week of December in a studio means that your week is booked at 12 months, guaranteed, each year for 50 yrs during that first week. 118 is about 10% more points than if you booked it at 11 months (which is currently 107 points), but if it were available at 11 months, you could cancel the fixed week, and immediately rebook it for the 107 points and save the 11 points. It's only worth the 10% if you can't otherwise rebook, and I'm telling you right now that Copper Creek studios for 11 months in December are going to be walked resorts and you will not get them each and every year. The guarantee will be everything.
If DVC decides to reallocate points later, (they can't increase the total number of points per resort, but they can rebalance them across rooms and seasons), you're protected.
If you want to use your points differently, you can cancel the guarantee that year and use your whole 118 points any way you like.
It's a great deal.
I have a fixed week Jersey Week Poly Lake View. I've never used the guarantee; I've always cancelled and used the points differently. But. I bought it with the idea that the guarantee would come in handy in the out years, 20 years from now. If I wanted to stay Copper Creek Studios in first two weeks of December, a fixed week there will come in handy as soon as the resort sells out.