Kendo is as useless in real-life as football, soccer, and all those other sports. As a sport, all it is about is self-discipline and improving your concentration. If you freak out and accidentally drop a grenade instead of throwing it, well, you just cost yourself your life and probably several others'. Kendo, or any martial art whatsoever, is not about the swords/weapons/fighting techniques, etc. It's about grinding some sense of discipline into yourself and improving your ability to concentrate on something instead of being a ADHD 12 year old who can't stand 6 hours of school a day.