Really bad financial decision.
Let's walk through some estimated numbers and see what this looks like.
Let's suppose you need 100 points per year for your vacation.
Option 1: $7500 up front, $550 per year.
You can buy the points for $75, so your up-front cost is $7500. Dues are 5.50 per point, so your dues on 100 points would be $550.
Option 2: $15,000 up front, $0 per year
You can rent points out at $11. So to cover your $550 dues you would need 200 points and you'd need to rent 100 of them. So 100 points rented at $11 per point = 1100. Your dues on 200 points would be 200 points at $5.50 per point for dues.
The difference between the two options is with option 2 you are spending $7,500 today to save $550 per year until your contract expires. The break even on this is 15 years assuming you can put your $7500 in a savings account and average a 1% return over that 15 year time period. I know that dues will increase and probably at a higher rate than what you can get from a savings account. So maybe the break even will really be 10 years. But to me that's still way too long to make this strategy worthwhile.
You are taking on a lot of risk for a very little benefit.