How would colonizing the moon benefit people?

The moon is an excellent source of helium-3 for future fusion. If/when fusion is perfected, the lunar surface may become the nearest good source of it--in time to replace diminishing, polluting fossil fuels. Because of its low gravity--weakening human bones--the moon may never become a good home for our descendants. But it can become our prime energy source. Indeed by building huge fusion plants on the moon, and beaming the energy to Earth, we may get the best of both worlds--vast energy without any local pollution at all. "Colonizing" the moon will NOT save us from the eventual death/expansion of the sun, since the moon is no farther fromit than we are, but it can contribute much to saving earth in coming centuries. That in addition to the benefits of a low gravity space base and observatory free of atmospheric distortions.