Non-secularly, the existence of God would have huge ramifications.
Now, more back on topic, science seems more and more trying to supplant religion (from the Creationist/Christian point of view). No longer is it very common to see reports from scientists stating that things were observed to be or appear this or that way. There is an air of finality and unquestionability that science isn't supposed to have. Religion and science are two subjects, just as mathematics and history are two subjects. And as is the case with all those subjects, they can at times merge, but are two distinct subjects. Similarly, all those subjects in their abstract form are perfect. However, in their unabstract (concrete?) form, you see that subjects can have flaws in them, given the imperfection of human creatures. Astronomers once believed that space was filled with ether, until Newton came up with his theory of gravitation. Common history once held that the existence of Sumer and Troy were myths. Now, those places and civilizations are believed to have indeed existed.
Christianity has an "opt-out." Because Christians believe that God (Who is perfect) gave mankind the Bible, the Bible can be considered perfect. It is taken by faith.
Science doesn't have that option. Indeed, almost by definition, science is supposed to be debated and tested over and over again until things become reliably clear. And yet, today, there are those who refuse to let science (in its concrete, non-abstract form) be questioned, and who all but reject experiments and observations which call into question what are today basic tenets (such as supposedly 65 million year+ organic material from dinosaurs being found in warm [non-icy year round] regions). That is detrimental to the advancement of science, much more so than letting Creationism be accepted as a rival alternative to and along with Macroevolution.
Creationism is a theological theory, which has it that God created the heavens and the earth out of nothing and that he stillsustains them. This is quite consistent with evolutionary theory provided that this theory is not confined to what Charles Darwin and Thomas Huxley taught almost century and a half ago or even to what is said today. Science is based on appearances and deductions from appearances. To a degree, so is faith. Jesus appeard to his disciples after his death and this is recorded. The materialist rejects what is recorded because nothing of the sort has appeared to him. Not content with this, many of them try to contend that the Gospels are fabrications as as to rule out any possibility of asking the question: Did the disciples really see Jesus? At bottom it is because they assume that such an event is impossible.