That deal is for Aulani, right? I was looking at it that too since we are thinking of a trip there in November or December. I haven't actually run the numbers, but staying cash at Aulani on that deal is very close to the cost of renting
DVC points I think. I will be using VGC points to stay there once my contract goes through, hopefully soon, and I think even using VGC points you come out a bit ahead.
Say you assume the worst case scenario and you buy expensive points (e.g. VGF), but stay at SSR everytime, do you still come out ahead?
I took a random week at SSR where I could find studio availability on cash. 11/12-11/19 is $2516 + $314.50 tax = $2830.50 for the week.
If you wanted to stay there on points, it's 98 points for the week (Choice season 14 points per night x 7 nights).
Say you buy 100 VGF points at $145 per point. Annual dues are $5.7119 per point. Assume that hotel costs and annual dues never increase.
100 VGF points x $145 = $14,500
VGF annual dues over the life of the contract (49 years) = $27,988
Total cost over life of contract = $42,488
Cash price for 1 week at SSR studio for 49 years = $138,695
As you mentioned, though, you can often get deals. 20% off is a pretty common one, so here are some other scenarios:
SSR Studio cash, full price = $138,695 (break even on year 8)
SSR Studio cash, 20% off = $110,956 (break even year 9)
SSR Studio cash, 30% off = $97,086.5 (break even year 11)
SSR Studio cash, 50% off = $69,347.5 (break even year 18)
100 VGF points, total cost = $42,488
DVC still looks pretty good if you use VGF points at SSR, IMO, unless you think you can get 50% off rack rates. It's rare (at least in the current environment) to get discounts at WDW as deep as that Aulani one, I wouldn't count on 30% off + free meals + $150 resort credits happening too often at WDW. I am not sure about Aulani, though. I'm guess cash looks a bit better there due to the better discounts, but I haven't looked that closely yet.
Edit: corrected SSR cost