What is the rationale behind buying life insurance for a child?

There are lots of companies out there that will sell you life insurance for your child. I am fully aware of the value of life insurance for myself and my wife (to provide for the other, or our children should we die), but why is child life insurance sold? If I lost my son, I would be devastated, and no amount of money would change that. So, is this just a legalized scam, or is there a virtue to this that I am missing?