If I'm understanding it correctly, DVCers have a very strong trading advantage in these networks. So, if we wanted a week in Hawaii (or anywhere-- just an example) wouldn't we be better off going that route than using our points to rent a place there?
As has been noted often on this board, a stay at DVC resort (such as BWV) gives you more value for your points than a stay at a Disney Collection WDW resort (such as the Polynesian). In the same way, your DVC points go much further if you do an II exchange than if you use your points to rent Concierge Collection accomodations.
When you do an II exchange, you get a full week. And, as with a DVC resort stay, your unit is clean when you check in, but you don't get daily housekeeping (with rare exceptions). Your unit is normally a resort condo, not just a hotel room (unless you exchange into a studio, which is similar to a hotel room).
On the other hand, there are good resons to use the Concierge Collection occasionally -- especially if you have some points you need to use. DVC members enjoy staying at some of the finests hotels on the planet, with the full service that such hotels provide. By using points, you're using money that you've already spent anyway, rather than spending $400 per night or whatever the hotel charges.
Yes, DVC has "a very strong trading advantage" compared to run-of-the-mill timeshares. But that still doesn't mean that DVC members are always at the front of the line when trading into the world's best timeshares. For example, Marriott Vacation Club (MVCI) owners have a priority at MVCI resorts. Whenever an MVCI resort week is deposited into II, owners at MVCI resorts enjoy a 21-day period of exclusive access to that week. The week is only made available to other II members (including DVC members) if no MVCI owner has grabbed the week during that that 21-day period. For a resort such as Marriott's Maui Ocean Club where it's likely that the demand by MVCI owners way exceeds the supply, it's unlikely that a DVC member will successfully get a week, even though it's on DVC's list.