if you care about mankind's survival on the planet, moral and spiritual progress is actually pretty important - just so we don't end up self-destructing. then again, even if we self destruct, we are but a tiny, tiny blip in the universe. sometimes the perspective and appropriate level of lenses through which that we should peer at life gives me problems.
perhaps, as Susan Neiman says, a sense of moral purpose is necessary to give life its dignity. We might not (and probably will not) get to some saintly ideal, but it is up to us whether we want to make progress.