Does the appendix serve any useful purpose ?
Not really. It has always been thought of as useless, but some believe is helps with the bacteria needed in you digestive system after an illness.http://www.independent.co.uk/life-style/health-and-families/health-news/the-appendix-does-have-a-use--rebooting-the-gut-396277.html .
it stores natural antibodies,its a backup
I've heard a theory that it used to be used in caveman days when people used to eat more grasses. We no longer eat grasses and have no need to digest them.