AirNZ are simply playing mindgames with their HVCs. Observe the rapidly mounting desire to be invited into this club and the thinly veiled indignation at the lack of respective invitations.
This will play out similarly to Facebook, Google+ and the enduringly naff Google-Glass. Initially, the Elite lounge will be invite only. EXCLUSIVE. They may use this period to iron out any kinks and complete the new lounges. Invitees will be unlikely to complain about hick-ups as they'll just be chuffed to be "in". Non-invitees will champ at the bit to gain access to this exclusive and rarified environment.
AirNZ will gauge demand and usage. Assuming this is sufficient, the elite lounge will eventually be opened up to a defined price/status point once they've built the requisite infrastructure, cache and hype.
This is turning out to be a rare master-stroke of marketing on AirNZ's part.