I don't claim to know what's going to happen with markets. But, if prices drop on a product I'm interested in purchasing, why would I not take advantage of the lower price?
Some may consider DVC an "investment." For many of us, however, DVC is not an investment in our portfolio, but simply a means to pay for desired vacation accomodations at a discounted rate.
By your logic, one could ask why people would consider even going on vacation, or buying any non-necessities rather than investing every discretionary dollar in the stock market.