Does everything need to written out before you can tell a reason for it? I do not think like that because some reasons are very easy to get. If everything had to be written down in the white paper, it would have been more bulkier. From the name halving, I know it means there will be a reduction of bitcoins, and when something is not so much and available everywhere, makes it more valuable to the few who have it and those who do not have it yet.