I'd disagree that purchase price doesn't matter based on amortization alone- because that ignores the time value of money.
Let's say I was going to buy 300 points, at either $70pp resale or $150pp direct. The net difference is $24,000, or $80pp.
For simplicity of math, let's assume both of these potential contract options have the same annual maintenance of $6pp, or $1800 in year one, and increased annual dues averaging 4% yearly.
If I were to buy the lower cost option, and invest the $24,000 saved in a stock index fund, all I would need is a 7.5% annual return to completely cover paying the cost of annual maintenance for the first year. With admittedly huge year to year variability, one could reasonably expect that the stock market will return more than that annually, over the long term (say a 30-50 year
DVC contract term.).
If the annual maintenance fees do go up 4% a year, and the stock market over several decades succeeds in returning an average of 11.5%- then by buying in at lower initial cost and investing the difference, I have literally covered the cost of maintenance fees for the entire life of the contract.
Now, we can all agree that most people buying aren't going to actually follow my example above- most would use that cost difference on something else. I just post this as a theoretical example of why saying "initial buy-in cost doesn't matter" isn't truly accounting for the value of the money saved by a lower buy-in cost.
Buy where you want to stay. Buy only what you want to use. And yes, buy understanding that you will spend dramatically more on the trips than you do on the DVC product.
Just understand that spending more money today really does make a big difference, when considered ten (or fifty) years into the future.