Just FYI, what points are REALLY good for is buying tickets for other people, especially those who are not the sort to make firm plans, or for instance, if your child wants to bring a friend on a trip. In such cases it can be worthwhile to buy the points even if buying the ticket with cash is a little bit cheaper.
The reason for this is that a flight purchased with cash will bank the cost if you cancel, but the money can only be used toward a new ticket for the *same passenger*. However, if you buy the ticket on points, a cancellation will send the points back into your own account to be used for any passenger.
So, your DD wants to bring her friend Ashley, and you agree, but 3 weeks before the trip, Ashley blows her report card in a big way and her parents decide that her punishment is not going. If you bought her ticket with points, you get those points back with no penalty, but if you bought them with cash, then you are SOL unless Ashley's parents pay for the flight.