The hardest part for most freight pilots moving into the 121 world is that the cargo (people) don't have to be at the destination. (I get that they do but bear with me.) I was talking to a DO of a 121 operation and I told him about my frieght life and he responded by saying that they don't have to get in.
Even though getting to the destination is pretty much the goal, it's not the desired option if it's between putting the plane full of people willing to sue anyone at the drop of a hat. CANPA approaches are easier because of how similar to an ILS (it seems, I haven't flown one). The other reason to do the is because it forces the flight crew to put the aircraft in a safe place to land were the dive and drive allows you to get into the airpory but puts the aircraft in a possible situation of low, slow, high drag, continously re-trimming the aircraft, and significant power changes where the turbofans may not be able to keep up if the pilot has been on duty for 16 hours and flying the last leg after a horrible day.
Also, the CANPA isn't designed necessarily for the US. ICAO has decided it was the best course of action because they regulate all corners of the world.
Or am I missing the point?