In terms of what there is to gain, Habitation of the moon would promote the development of more self sustainable technology, new and improved materials (lightweight rad shielding, cheap building materials such as regolith construction, etc), higher semiconductor yields, and cheaper methods of producing previously very expensive compounds and structures for the pharmaceutical industry.
IIRC the economics of a moon base (which is presumably what you're referring to) don't make sense in terms of fuel costs vs potential revenue. Could you illustrate what a "cash crop" might be for the moon?
The economy doesn't come into it. Consider the continued operation of such things as the IIS, which have no compelling reason to continue to exist. Research alone is a good enough reason, plus the potential for sponsorship/tv rights etc also recouping some of the costs for such things
well, the moon would likely only serve for research purposes until space faring society is a bit more established. The most likely "cash crop" for the moon would be serving as a drydock for spacecrafts. The low gravity would majorly reduce the cost and remove the size and profile constraints of said spacecrafts.
