Navigation
There is some doubt whether the Southern Cross as such was important in navigation. Pacific Peoples, including the ancestors of Maori, certainly used stars as part of their navigation, but they did not regard these stars as a Cross and may not have recognised that they pointed to the South Celestial Pole. European explorers also used stars for navigation but had instruments that meant they were not reliant on a particular constellation such as the Southern Cross.
Nonetheless it can be handy even for modern-day New Zealanders to be able to use the Southern Cross to find the direction South, if lost in unfamiliar surroundings.