Hi Chris, The difference is credibility.
Christians go into the scientific arena as a very bad witness.
Many of the arguments used to defend the young Earth position are misinformed, inaccurate, and just plain wrong. And besides all that the Bible never says that the earth is only 6000 years old. So for anyone to dogmaticly teach this is wrong to start with. Genesis is not a scientific account of the creation and should not be presented as such, anymore than Revelation should be used to label the Pope as anti-Christ. Don't get me wrong, I don't think science is perfect and scientists make mistakes based on assumptions, and yeas there are probably some that hide evidence that supports the Christian view.