One of the great strengths of the theory of evolution is its explanatory power. Heredity with variation explains the distribution of similarities between different species over time. It explains the results of many, many experiments. Of course, Creationism, with an unfalsifiable, unknowable, all powerful magic man can explain it as that deity's random whims. That is, of course, one of many fatal weaknesses of Creationism, because it has a lot of things it can't explain. It boils down to this:
Why is the world NOT something else? Evolution explains quite well why we have nested hierarchies indicative of branching processes. Anything else would be a violation of heredity or require a new phenomenon to explain. Creationism, thanks to the unknowability and omnipotence of the deity, seems to suggest anything was possible and it was just random chance that he happened to be in the mood for making a universe that looked like it produced a diversity of life through evolution. As they would probably say, humans and chimps have common ERV sequences, not because they had a common ancestor with them, but because their deity randomly decided to give them the same sequences in the same locations. They'd probably leave off the "randomly" part, though.
Move the topic to cosmology. The Big Bang theory explains why we see the expansion of the universe and predicted things like the microwave background radiation of the universe. Creationism essentially "explains" this by random chance again with the unknowable whims. It could have made the universe any other way, but randomly chose to make it look like a Big Bang universe.