I did not try to do any calculations but it might be better to fly for 150K points using cash and point tickets than to buy 10K basic points for it (I mean you might earn more points and still get the flying, if you can use it to some good effect). I am sure that someone here did the calculation and found good routes

Buying points is interesting in two scenarios: when you absolutely do not have time to fly right now, and if your qualification period is over (if studentCPH is right). The latter is a rather cool service, I think. Never heard of it before.