for critical deployments, the enterprise version has high availability, cross data center replication, and more. you can use the free edition however you please.
I currently use beta 1.0 for one of my tools and it has been functioning for years without a problem. I think they are just saying don't sue us if you use in production and didn't pay for it :-)
Ehhh. Do they mean that the Community Edition is only usable for development?