I am in middle TN, USA. I have just gotten started in this sport. I decided to train for racing from the get-go (southern term, y'all!) so joining a club was a priority of mine. The benefits are: training with a group, lots of experienced riders to help with problems, riding with the group makes you ride faster; thus increasing your average speed faster than on your own (I have increased my average 1.5 mph in less than a month.......which I think is substantial). Riding with a group keeps you accountable, too. Makes you stick with a diet and exercise plan and makes you work hard to stay competitive. If you don't ever compete, how are you going to improve?
Just my thoughts!