Regions at the south pole remain in perpetual shadow. Temperatures there drop below −250°F (−157°C). Water ice deposits exist in these craters, discovered by radar and spectroscopy. These ice pockets are billions of years old. They could be harvested for drinking water, oxygen, or fuel. Permanently shadowed regions also preserve ancient solar system material. This makes the lunar south pole a prime exploration target.
It matters for sustaining long-term missions and in-situ resource utilization.
It also provides a glimpse into solar system history preserved in ice. Ice can contain clues about comet and asteroid impacts.
Some craters haven’t seen sunlight for over two billion years.
NASA [nasa.gov]