Consider if those "direct benefits" are worth it to you.
Right now, the main economic benefit is discounted annual passes. With one trip per year, it's hard to make that cheaper, even with the discount, over buying regular park tickets (unless you vary your trip each year by a week, where you travel 51 or less weeks after your last trip).
There's a minor economic benefit in discounts, but many of those discounts are shared with holders of a Disney Visa card.
The other big benefit is the ability to book Riviera (and future DVC resorts to be built). I'm not sure how much of a real benefit this is, since it's clear that there will be an active Riviera rental market, just like there is for the "legacy 14" (DVC resorts built before Riviera). Resale points purchased today can book at any of the legacy 14 at 7 months.
Booking cruises,
adventures by Disney, and using points for cash room reservations are terrible uses of points. It's so bad that David's point rental business has an "exchange" program for cruises. They find someone to rent your points, and take the money to book you a cruise saving you 25% or more over what you'd spend on a direct exchange with Disney.
There's a lounge at Epcot that is direct owner only. Expect this to disappear as Epcot is re-developed. There are, occasionally, DVC only events like Moonlight Magic and the Soarin' backstage tour. The MM events are limited to the number of attendees, and never occur near Thanksgiving/Christmas. The Soarin' backstage tour is limited to 20 people once per week-it is very difficult to book.
If you do decide to buy some of your points direct, you can buy your main resale points at one resort (like BLT) and the 100 points at either the same resort, or another resort. If you match your use year, you'll be able to have one online account and see both contracts. If you have all your points at one resort and one use year, you can use them together seamlessly. I have 3 contracts, all the same use year and all at BLT, one purchased resale, and two tiny ones purchased direct (when I purchased the direct contracts, the minimum number of direct points to get benefits were 25). My wife and I had stayed at or visited all the DVC resorts over the years, and knew that BLT was our "home", so we never considered having points at multiple resorts or doing split stays in one vacation.