So all you have done is provided on example where you have decided it’s worth it to buy points.I want to go A to B. The airline(s) prices it as $X. Whether of not you think its worth it, that's the cost. If I had no points, I'd have to pay that. As an alternative, I can earn or buy points and redeem for the same flight. So I've saved $X-(cost of points). The actual 'worth' of the flight doesn't matter to me - I had to do it and I got it much cheaper by buying and using the points.
But as the saying goes, one swallow doesn’t make a summer. I’m sure everyone can supply many more examples where they have decided they don’t want to pay that much. If anything you’ve proved my point, in this one circumstance you are prepared to pay that cost, it’s a bit extreme to extrapolate this to mean you’ll alway do so.
