Bob,
SCCA rules require a track get certified and run a successful regional race before they are approved to run national races.
Say what you will about SCCA and convoluted rules, having been RE of a region getting a new track certified, this process really does a good job exposing and fixing any safety flaws in the track. Simple things like spacing between armco bands, bolted tires, etc.
I'm not 100% certain, but I think having the certification is beneficial to the tracks insurance rates as well.
Scott