Macro is so you can get in there really close to the subject. Like with raindrops...
Here is an example:
It helps you to be able to see the fine details. You can't get that with just any lens. It is like focusing with your eye - you can only get so close before a subject gets blurry. If you get a magnifying lens to assist then you can get closer and see more details. I hope that makes sense.
Here is another example:
