alt Hacker News>we still have a useless appendix
This was believed in the 20th century, but we now believe the appendix is actually useful, and is basically a fail-safe in case the intestinal flora are wiped out; some will survive in the appendix and repopulate the intestine.
Which is an incredibly specious conclusion because when would the gut fauna ever be wiped out? For the evolutionary history of mankind, antibiotics did not exist, and people without an appendix (such as myself) have no medical need for any special treatment after going on antibiotics.