What is the importance of the Matching system?

The hostess tells everyone that they can read the courtship guidelines later on because there is plenty of time. Cassia knows that it is true. The Society has insured that they live better and longer than anyone else who has lived in the history of the world. This is mostly thanks to the Matching system, which produces offspring that are healthy bother physically and emotionally. It's her world, and it's run by rules. She is now allowed to touch Xander, and she is free to dream about him.