Thank you for your inquiry. These are questions that often come up and you have stated them well. Does the creation-evolution question really make any difference at all? Sometimes we wonder that ourselves. Many people do not care a fig about this issue, and if it does not interfere with their relationship with Jesus Christ, I am sure they are going to receive their reward in heaven just as I. But, if you have ever ministered on a college campus, you will find that intense pressure is placed upon young people to abandon their faith, and the tool that is used is evolution. I have personally seen many turn away from their faith as soon as it is challenged in the classroom. When they turn to the church for answers, there are none. When they drop out of church as soon as they leave home, the parents wonder why. I believe it is because these foundational questions about who we are, where we came from, and why we are here are never discussed. That is why The Revolution Against Evolution exists, to field these questions of inquiring minds to whom they become stumbling blocks for their faith.
Another problem is that there are many who use the theory of evolution as an excuse, a justification for why they are living apart from Christ. I cannot believe that you have never met anyone like this. It is true that most people, when they accept Christ, do so for emotional reasons, and for the most part they have had some familiarity with the gospel from past church experience. But, there is a generation of people growing up today that have never even been inside a church or heard the gospel at all. To these folks, the preaching of Christ and the cross is foolishness. "Why do I need a savior when the story of Adam and Eve is just a myth?" they ask. And for the most part, the church has let these people down, for if the story of Adam and Eve is just a legend, then there was no fall of man, no original sin, and no need of the cross of Jesus Christ for redemption.
There is a misunderstanding when we talk about evolution. We should qualify our discussion by talking about microevolution, which is observed changes within specific limits, and megaevolution, the idea of gradual change and emergence of species from molecules to man. Creationists do not dispute that microevolution takes place, in fact, it is a keystone to their theory.
Creationist believe that microevolution takes place in two different ways: (1) laterally, that is, reshuffling and rearranging existing genetic information or (2) downward, where through mutation genetic information is damaged or destroyed, inactivating a biochemical pathway that leads to death. We do not believe that new genetic information emerges from the mutation process. Instead, we believe that in His original creation, God planted all of the genetic information found in nature today, and it is either turned on or turned off to produce variety. Microevolution is simply the change mechanism God built into his creation to produce the mind-boggling variety found in nature. "Devolution" is the mutated changes that take place to the detriment of the organism. This is part of the curse placed upon creation after the fall of man, and it causes disease and death. This is also why we need a Redeemer, to deliver us and give us life after death.
We believe that the idea of megaevolution strikes at the very heart of the gospel. It is a message that says that man is only a part of a long drawn out process that took place over millions of years; that molecules became proteins and DNA, which evolved into cells, and gradually evolved into dinosaurs, monkeys, and man. Man, as the pinnacle of evolution, so they say, has no need of God, and he determines his own destiny. He is responsible to no one but himself.
If Genesis is true, who sets the rules? God does. If Genesis can be discredited, who then sets the rules? You do. If you believe Genesis to be a myth, then you are not accountable any more to God. You can make up your own rules. This is reflected in society today. Everyone has a different opinion on what is right and wrong. It is all based upon feeling. In fact, a popular philosophy today is existentialism, the idea that what's right for me may not be right for you, and your morality is subject to the individual. "Do your own thing" is a popular extension of this idea, and this is directly related to our society abandoning Genesis as straightforward truth. Even Christians have become existentialists, choosing God though it makes no sense to them scientifically. But they split their mind into parts, one that believes God, the other that carries on with everything else in another physical world.
Now I believe as you do that Christianity is to operate by faith, and not by sight. But that does not mean that we are less spiritual if we find concrete facts that support our faith. In fact, I like to think of science as "thinking God's thoughts after him" as George Washington Carver so aptly put it. Our Christian faith should be such as to apply to all areas of our life: to the arts and sciences, to mathematics, literature, the media, and our world-view. For years, we Christians have been content to allow the secular world to box us into a cubbyhole where we can sing our Christian songs, worship God, and do our Christian thing without having any effect on the world around us. Science has been stripped of any Christian influence, and has been defined to be mechanistic only. That is like saying that we are going to discuss color, but we can't say anything about red.
I for one do not want to be double minded (James 1: 6-8), splitting my life into a Christian compartment for Sunday, and a secular compartment for the rest of the week. To me, everything has to make sense in a Biblical framework, or none of it makes sense. That is why I grapple with these tough questions, and dare to look foolish in front of my atheist colleagues who mock me publicly. I got into this after studying biochemistry and computer science, realizing the tremendous amount of engineering that needed to take place in order for life to begin. Hundreds of scientists have come to the same conclusion as I, that the answers to the origin of life does not come from chemical evolution. It is that same chemical dance between DNA and proteins in a complex manufacturing process that convinces me that megaevolution cannot work. The problems with forming the original set of proteins and DNA apply to the problems of creating a viable evolutionary change. Mutations cause dead-end chemical pathways, and are an enemy to constructive change in an organism. If you don't believe this, select a dozen biochemists, line them up, and ask them to volunteer to have their genes mutated, and see what their response might be. The confusion comes when they misinterpret lateral redistribution of existing genes created by God. They believe they are seeing megaevolution in progress.
For more information about the importance of the Creation-Evolution issue, I highly recommend the video "The Genesis Solution" and the accompanying book by Ken Ham of Answers in Genesis. I certainly have not covered everything here, and I recommend that you research other articles on this site and the web sites I have linked.