It's not unusual for owners at dual-affiliated resorts (or with multiple resorts) to ask, "Which exchange company should I use?" A common response is, "Where do you want to go? The various exchange companies each have their niches, with better inventory in some locations than in others."
So, by seeing desirable resorts, like the DVC resorts, some people may opt to join a particular exchange company and deposit their week, if they think they'll have a good chance of trading in to those resorts. It may not make a huge difference but it makes sense to me as a business move. We can disagree.