For real, resource extraction is a big one. Finding ice means they can make, besides water, oxygen and rocket fuel. Not to mention that shelters for radiation are incredibly hard to make without a huge amount of mass, which we cannot efficiently get into orbit without a space elevator. Hence being able to extract it from the location of the colony, say dig into the ground or build thick walls with bricks made from soil, is necessary for long term survival of the inhabitants. I think it is cool that due to these reasons having air balloons over Venus might even be a better option due to it having a protective atmosphere.