The only plausible good reason for mining the moon would be to get materials for large-scale construction ter space, because lifting them off the moon is far lighter than from Earth.
Valuable minerals are uncommon compared to regular rock on earth.
If it is the same on the moon, the amount of mass taken away by mining will be insignificant beside moon’s total mass. Continue reading Could wij mine the Moon if wij substituted the taken mass? Worldbuilding Stack Exchange