Poetry is a way of expressing yourself. Writing can be seen as therapeutic. It can surely help to write down your thoughts, it has helped me a lot. I find it is the deep of things that matters most. I find it is a very good way to converse with my inner self about what is going on within and without in my own world and in my own perception.
Poetry and stories can definatly help as in stimulating metaphores which can open the mind. I also think writing can help looking at yourself, emotionally, or in any kind of process, a proces of healing, mourning, or simply personal growth. I surely think it is considered art as well, the art of you, the art of self expression. I dont think one should be busy With the definition of art or poetry.
If you want to Write, just Write, just Write, just WRITE