Dreams help you learn. Dreams affect your mood the next day. Dreams can occur during non-REM sleep. Dream logic is neurologically logical. You get in touch with physical and psychological pain in dreams. Dreams are very useful and informative. http://m.mentalfloss.com/article.php?id=51228
A way to use dreams functionality is through Dream Incubation described in my book Dreams: Guide to the Soul which is at http://www.drstevenfox.com (Chapter 34).