I have not yet used this option with my points, but I will.
I agree that you definitely save more $$ using the points for flights, but good luck getting seats if you are not an Elite status member. A good friend of mine accumulated well over 500,000 miles in his account while he was on the road, but since he hasn't travelled much in the last two years, he has lost his status. He has tried unsuccessfully twice to book flights with points and could not get seats because he has a family of four and could not book the seats on one flight.
If you can plan far enough in advance and you don't need too many seats, you will probably be able to book. But if you can't get seats, using the points for other rewards (park tickets, rooms, rental car, etc.) is better than them wasting away waiting for AC to actually free up seats on its flights to its customers.
BTW, I have never had any trouble with AC, but thought that this part of the reality should be out there. I had the same problem with flights with AirMiles, so I used those miles for park tickets as well.