A critical point is that regardless of whether
DVC is a direct purchase or via resale, ALL perks can be modified/discontinued by Disney. The DVC annual pass discount hasn't always been there and may be dropped in the future if Disney deems it beneficial to themselves.
I guess this comment is made only to make sure that nobody buys DVC based on the perks and benefits beyond what is in the contract. If staying at DVC resorts for a somewhat "locked in" cost (escalating every year through dues inflation) isn't a good enough reason to buy DVC, then the purchase shouldn't be made regardless of how it is made.