Subs could be useful to protect/attack shipping or military assets that are protecting/attacking shipping. It does seem improbable that we will see large scale

Subs could be useful to protect/attack shipping or military assets that are protecting/attacking shipping. It does seem improbable that we will see large scale land invasions of developed countries. However, European nations also thought that was improbable pre-WW1. It's not crazy to err on the side of caution here. After all you could ask the same questions about the Chinese military build-up --- no-one's going to invade mainland China, obviously. NZers definitely don't want to be in the nuclear sub business but I think the majority of NZers are concerned about the direction of the CCP and are happy to be part of ANZUS and Five Eyes. Sure, we want to keep taking China's money but if push comes to shove there's no doubt which side we're on.