The following are some reasons:
This whole issue of how literally the Genesis account is to be taken is a classic example that illustrates the importance of sticking to what God's word says even when it is contradicted by human knowledge or wisdom. When Christians first learned about distant starlight (that had apparently traveled for billions of years) reaching earth, many felt that the 6000 year time-frame of the Bible was wrong and looked for artificial ways to fit the Bible with what the scoffers were claiming. Some Christians held their ground and said that perhaps God created the light "on its way" or accelerated the light in the past to make it reach us. Today, Einstein's Theory of Relativity helps us explain how only 6000 years has elapsed from the earth's viewpoint (which is how Genesis was written) although a person traveling with the starlight would experience billions of years of time. God's word is true! It is only contradicted by partial or imperfect scientific knowledge!
Dear believer, hold your head high! When you come across an evolutionist, look him in the eye and say that God created the world six thousand years ago, and that God is love - the suffering and death is because we messed up! No discovered scientific facts contradict this. As Creator of a perfect world, God has the authority to demand perfect standards (Romans 3:23) today, and judge those who don't comply. And He's also been loving enough to provide a way of salvation!