I believe if we don’t reach-out don’t try to do things that are thought impossible or unpractical, then we don’t learn, we don’t invent, and we achieve very little. Just about every civilization that ventured out, invented or brought back knowledge and information to benefit their society or destroy it, but they learned something.
Presumably there comes a point where we can harvest rare-earth elements from somewhere. And we are close to making space tourism viable.
And I suppose the aim of all exploration is to not only search and research new areas but to eventually colonize them, be it Moon, Mars, Titan or some exoplanet.
In great scale, mankind and civilization is fragile and vulnerable as long as we're confined to this one planet. If we are able to spread to the stars, no single disaster can destroy us. Well, not as easily, at least.