Well this one’s easy: an improper understanding of the world is harmful. An accurate understanding of the world helps: learning certain aspects about the human condition permits you to achieve enlightenment, though meditation helps too.
That claim is easy to understand: whether it’s accurate is another matter. Within Buddhist mythology, the Buddha would give a lecture and half the auditorium would attain instant nirvana. But by the time Buddhism passed out of the oral tradition, attaining Nirvana was something only a few experts could do. Most believers would simply try to accumulate good karma in this life, in the hopes of improving their condition in the future and succeeding lives. Still later, certain sects established the goal of achieving Nirvana in this lifetime.
Personally, I wouldn’t get too bogged down in the salesmanship. That said, I find the philosophy useful in its way.
If you are asking what Buddhists believe the nature of the world to be… well you are asking what Buddhist doctrine is, right? http://www.thebigview.com/buddhism/fourtruths.html
