Not so long ago, surgeons regularly removed and tossed the appendix, when doing other abdominal surgery, just in case the patient might get appendicitus some time in the future.

Apparently that does not happen now if the appendix is healthy. As it turns out, the appendix is a very useful part to have about, because it can be used in future reconstructive surgery of the bladder and other related parts in the patient. Perhaps the jokes about using foreskins in reconstructive surgery are not that far fetched. LOL

Also it has been discovered recently, that the appendix also serves a very important function during fetal development and in young adults, with regard to the immune system. So much for vistigial or superfluous bits. I'm certain we haven't quite learrned all there is to know about the wonderous design of the human body.