Well my understanding of Air Points (limited, I grant you) is that it is like the current AN system, whereby Y gets 70% credit for anything but full fare, and other dodgey type things like this. To compare, a program like UA Mileage Plus is great with 1:1 credits (for most flights), minimum mileage of 500 etc etc and others like LH Miles & More, as Rudi points out many times, is great for paid C/F travel as the bonuses are impressive 2x/3x but also count towards status.

Also as you point out if NZ1/2 is the prime route you want to upgrade on, and it would be nigh on impossible to get an upgrade seat, then the points earned may well be useless for the requirement--so better to look elsewhere, IMHO.

Of course, your mileage will vary

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RichardMEL, UA 1K
A Star Alliance Member.