Is it possible to make emergency calls on a cellular Apple Watch, WITHOUT an iPhone in range, and without the watch being on its own carrier plan?

I'm considering purchasing an Apple Watch SE. Even though I will never consider paying for an extra cellular plan for a watch, I am willing to pay the extra $100 for the cellular version of the Watch purely for emergency calling. I would just like to have the peace of mind, knowing that I can dial emergency services on the off chance that I have only the watch on hand. However, it's not entirely clear to me whether emergency calling works in NZ without a plan.

Apple's website has the following page:

https://www.apple.com/watchos/feature-availability/#communications-international-emergency

"International Emergency Calling"..."This feature is available when traveling abroad to the following countries and regions."

It lists New Zealand, but has the following fine print:

"Device must have been set up for cellular service with a carrier but does not require an active cellular plan."

What does that even mean? How would I "set up" the watch for cellular service without having a cellular plan? All iPhones are capable of emergency calling even without a SIM card installed, so why would the watches be different