IMC daytime- not visual, press the buttons and off you go with the autopilot on the whole time.
IMC daytime- get visual, lots of visual cues and can see all of the obsticals.
Get visual at night time and you cant see all of the obstacles plus you have all of the human factor issues of flying at night, depth perception, high low errors etc.
Also depending on your approval, unlike Australia where there are no real obsticals around airports, in QT you may not be lined up with the runway (the remarks at 7000+ feet are within 3 miles of the airport) on the RNP and there's little kicks in the approach below 1000ft to line you up. Add to that the PAPI can't be used beyond 4 miles I think.
Line up with the runway and on slope at 5 miles, you'll go very close to losing your left wing.
So there is a big difference between IMC day and night Visual segment.
The flights will be very popular, unlike some of the "this will be great for australian skiers getting home because anything NZ does is for Australia" mentality, (I've seen it in Australian press) there are many flights that leave Auckland every night up to Asia and the Americas and I'm sure the night Queenstown flights will be timed to meet these.