What sticks out to me is that the distance to any location in the universe that could possibly support life is multiple light years away, if not dozens to hundreds of light years away. The time just to accelerate to light speed would make light-speed travel seem to be very inefficient, since life forms would not be able to withstand the G-forces above a certain level. I know there is theory on how it could be done, but sometimes common sense over-rides theory.