Absolutely, those are very good points, though not all of those problems are best solved by manned missions (e.g. exploration can be more efficiently performed

Absolutely, those are very good points, though not all of those problems are best solved by manned missions (e.g. exploration can be more efficiently performed if life-support systems are unnecessary). Increasing human survival odds definitely does require manned missions. But, from a cultural enrichment/learning/individual experience perspective (which I, perhaps incorrectly, assumed the parent comment was referring to) a sufficiently accurate simulation with appropriate man/machine interfaces is a far more efficient solution than manned spaceflight over interstellar distances (provided people can get over their discomfort with the ontology of simulacra).