Why does Haskell have Data.Sequence?

Question

Why does Haskell have Data.Sequence? Aren't (lazy) lists already the most general forward iterators possible (by virtue of being free monoids)?

Answer 1

The details are mentioned on the first paragraph on hackage. As pointed by @AndrewC they offer many operations efficiently example concatenating two sequences, viewing the right end of a sequence or adding elements at the end of a sequence.