Wow, I was just reading today that most cases of appendicitis occur to kids between 8 and 14. Hopefully they can rebuild it or create an artificial one. It is important to good gut health. It keeps a reserve resevoir of good bacteria to replenish the gut if something depletes the bacteria in there.Haven't missed mine a bit in the past 45 years or so.
Yoghurt after tummy illness is a simple fix for the reservoir issue.