Encouraging writing - in all age ranges - is vital, I think, for all sorts of reasons. Not only is there the joy of being creative, becoming involved in the arts is known to be good for physical and mental well being. I found I didn't know what I could write until I actually started writing. I never expected to be a published author of flash fiction (From Light to Dark and Back Again) or a blogger but I love both and am still hoping to do something with my unpublished novel at some point. I love the sheer scope of where writing has taken me and where it will continue to do so. I have made friends online and in person as a direct result of writing.
Also creative writing encourages reading and that has got to be reason enough to write in itself!