That's not true. The primary reason we want to travel to other planets and stars is because we want to learn more. There's only so much a telescope can detect. Without going there, you won't even have what to simulate.
And the other reason for why we want to travel is because we want colonies. Given consumerism, population growth and the destruction of our environment, it gets pretty clear that we need a backup plan. This is why we still need human spaceflight, even if sending robots is much cheaper for discovery and learning purposes. And again, simulation is pointless.
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).
