The novella is significant because it recounts the time when the Culture comes into contact with Earth (circa 1977). The other stories are interesting as well, but not really memorable (except maybe `Road of Skulls', which is very short, not very subtle, but still manages a surprise at the end).
This is worth reading only for completeness for those who can't get enough of Iain M. Banks. I would, however, discourage anyone from reading it before they have read any of the other novels, as it doesn't show what Banks can really do when he is let loose.