This is my eighth year of CP. I fly about 30 segments a year almost all with my wife. So the fares I didn't pay have to add up to $4,000+. $30,000+ over the last nearly eight years. Of course, without the CP we'd do less traveling, or only one of us would travel. We see it as a very great value.
Also, some other airline might be cheaper, but being able to change, which we do very frequently, is a great benefit. That, free luggage, and the CP - if WN goes there, we go on WN.