It's absolutely true that for traditional weeks the long-time TUG admonition to always buy retail is still 100% true. There are a couple narrow exceptions to that rule, however, for Marriott Vacation Club points. It sounds like the OP may have taken advantage of one of those exceptions.
Since from your signature you appear to own only Vistana weeks, you may not know about some of the nuances of the MVC system, where some developer purchases can be very competitive with resale. Here are two:
1) Marriott no longer sells developer weeks and only sells DC Points from their MVC Trust now. However, if you know to ask or you don't bite on their offer of points for $10.50 to $12/point (after typical discounts), they will often offer to sell (brokered by their internal resale group) an enrolled resale week, plus an amount of Trust points that matches the point value of that resale week. For example, a week worth 2500 points, plus 2500 Trust points. The 2500 Trust points will be at their standard prices, so if they offer to sell you those at $11 each, that's $27,500. The resale week worth 2500 points might only cost $9,000, though (depends on what you buy, so this is just a theoretical example). So, for $36,500 you would get 5000 total points - an average cost of about $7.50 per point. MVC Trust points sell for around $4-$4.50/point on the secondary market, but then MVC requires the buyer to pay MVC a $3/point activation fee. So most resale points also cost in the $7 - $7.50 per point range. These are obviously only example numbers, but they are typical for these kinds of packages that have been bought by TUGgers (on TUG we call them hybrid bundles). Many TUGers have elected to take this approach because the cost is similar to resale, and by buying from Marriott, we have some protection of future benefits that pure resale points may not offer.
2) From time to time (about once per year for the last four years or so) MVC has allowed owners of externally-purchased resale weeks that were bought after June 2010 (the start of the DC Points program), weeks which are normally ineligible for points enrollment, to be enrolled if the owner purchases at least 3000 DC Trust points at standard $10-$12 discounted prices. If those resale weeks are point-rich weeks like Hawaii, Aruba, summer beach weeks, etc., the average net cost of the points added (the new trust points plus the enrolled points) can result in a very attractive cost per point, often below $6/point. For an owner who wants his/her resale weeks to be able to play in the points system, this can be very attractive.
So, there are a very few restrictive cases where a developer purchase could make sense for an owner who wants to fully participate in the DC Points program.
