The DVC is expensive, for what you get. That expense is compounded by the fact that most DVC members must take out a loan to purchase those initial 150 points. I don't know too many young couples that have that kind of change just laying around. Also, as all DVC members know, you never want to stay in a DVC resort on a Friday or Saturday night because it's just too expensive! Financially speaking, a young couple would be far better off investing that chunk of money rather than spending it on a DVC membership. They can obviously go to WDW for the same length of time (or more) and by staying in a moderate or value resort they save money compared to the typical DVC member.
DVC membership generally is not worth considering unless you have the upfront cost in the bank (in other words, you don't have to borrow the money) and you plan to vacation at Walt Disney World every year. When considering a DVC membership, it's a good idea to get out a calculator and add up the initial buy-in cost, the annual dues times the number of years your points will be active (be sure to account for annual dues increases), and any interest you would be paying. Divide by the number of years you'll get out of the membership to calculate your "true" annual cost. (Of course, that doesn't include the lost interest you would have earned on the money you paid up front for the membership!)
For many people, it just doesn't add up. If you put the same amount you would have "invested" in buying a DVC membership into a secure investment, and each year add the same amount of money you would have paid in DVC fees, you'll have more than enough to take a nice annual vacation at Disney (or elsewhere) -- plus that money remains liquid and available in case of emergency. However, for some people a DVC purchase is a way of committing to an annual Disney vacation, and that may outweigh any financial considerations. Only you can determine if DVC membership makes sense for your situation.