This fact has nothing to do with the question of whether the Koran is the revealed word of God. Even if God did speak directly to Muhammad, there is still a serious intellectual challenge involved in figuring out how to apply what he said to individual life situations. Words get their meanings from the context in which they are said, and for the Koran that context no longer exists. To simply superimpose our own context on words said a thousand years earlier runs the risk of giving the words a completely new, and wrong, interpretation. That is what people do when they read the Koran without any knowledge of Islamic history, or without consulting scholars who are familiar with the nuances of the original Arabic.
The Hadith were preserved partly because Islamic scholars were aware of this problem. Some modern Islamic reformers want to throw out the Hadith, because only the Koran is the word of God. I agree with part of their intention, because many of the more extreme prohibitions advocated by fundamentalists are derived only from the Hadith. I think however that tremendous insight and benefits can come from reading the Hadith, and other aspects of Islamic history, as long as we remember this passage from the Koran.
Do you see that which God has provided for you? You make some of it Unlawful (Haram) and some of it Lawful (Halal). Did God allow you to do this? Or do you tell lies about God?
What this implies to many of us is that only the Koran should be used as a source for taboos and prohibitions, because only the Koran is the word of God. Most of the prohibitions imposed by fundamentalists (including my least favorite, the prohibition against music) have no basis in the Koran and are derived solely from the Hadith. We can however, reject these Hadith-inspired taboos, and still value the Hadith as a way of enabling us to more fully understand exactly what the Koran was saying.
However, once we have understood the Koran in its historical context, there is still the problem of how to apply its teachings to the present time. That requires careful reasoning (ijtihad) and careful use of analogies (qiyas). There are no exact parallels between what was happening in 6th century Arabia and what is happening now, so we have to using our wisdom to decide which parallels are legitimate analogies and which are false analogies. Do all rules about camels apply to cars? Do rules about swords apply to guns and atomic bombs? Obviously some rules do, and some don't, but the Koran cannot tell us which is which. We must puzzle it out using the wisdom that Allah gave us, come to the best answer we can, and be humble and open-minded when discussing our interpretations with those who disagree with us.