OR is it that it's not GOD that wants us to know those things but man that wants us to know those things under the guise of God?
For example you and I would probably agree a lot on morals and values as far as what they SHOULD be. Where we would differ is where they come from. So if you can for arguments sake say the entire BOM is practical fiction and I could for arguments sake agree the same for the Bible....then what we can equate them both to being are some good ideas and some bad ideas written by man.
If we start to say this is allegory and that is real, where do we draw the line? How or who gets to decide? If we can agree on the moral of the story is there any reason to attribute any of it to God or do we do that to help safeguard that people will obey the rules we agree upon and us something like hell as a device to scare them into shape if they won't bow to our will?
Possibly, though the premise I was focusing on was that God was somehow involved in the process of the making of the Bible and Book of Mormon. If that were the case there would arguably be a lot of value in the book, even if it means the history has to be viewed as allegory or metaphor. If the Book of Mormon were purely the work of Smith as some sort of well meant directive as to how one should see God/live one's life and so on, it would be more problematic for someone to try and discern if there was anything of value in the book. After all, it would just be one man's opinion (or some collusion of several people's opinions), and would have no more obvious value than our own independent ones.
So, if it were truly the history of an ancient people and their dealings with God, arguably the entire thing is quite valuable as a resource in understanding God and how He thinks we should live. If it were a metaphor in which God had a hand in developing, it arguably still has a great deal of value as a source for moral guidance and doctrine. We mustn't forget that although the Book of Mormon does recall historical stories, a significant portion deals with integral Christian doctrine that would not necessarily be undermined by the history of the people explaining them being a metaphor. If it is the work of a man, or men, then it is no more valuable to you or I than any other decent book exploring Christian doctrine.