Why assume that novelty is a criterion for the worth of someone's literary output? Things can tread familiar ground, use familiar forms, and still be remarkable or worthwhile. (Imagine saying to Shakespeare: "Why write a book of love sonnets? Didn't Petrarch already do that?")
That said, I haven't read more than a few pieces by Carson and I'm curious to read more.
That said, I haven't read more than a few pieces by Carson and I'm curious to read more.