Use-cases for Streams in Scala

Question

In Scala there is a Stream class that is very much like an iterator. The topic Difference between Iterator and Stream in Scala? offers some insights into the similarities a

Answer 1

Stream is to Iterator as immutable.List is to mutable.List. Favouring immutability prevents a class of bugs, occasionally at the cost of performance.

scalac itself isn't immune to these problems: http://article.gmane.org/gmane.comp.lang.scala.internals/2831

As Daniel points out, favouring laziness over strictness can simplify algorithms and make it easier to compose them.