Karate looks incredible. The crisp white gi, the belt, the bow, the snap of the sleeve when a black belt fires a reverse punch into the empty air in front of him. It is the most photogenic martial art ever invented, and that is the first clue. Anything this good-looking is optimized for the movies, not for winning.
Start with the kata, the soul of the art. These are gorgeous, decades-polished routines performed against a committee of invisible attackers, men who do not exist, attack one at a time from the four cardinal directions, and politely wait their turn. A karateka can spend twenty years perfecting a flawless counter to an assailant who has never thrown a punch, will never throw a punch, doesn't know how to grab, doesn't coordinate with his buddies and is mostly notable for not being in the room.
Then the signature flex: breaking a board. A board is a stationary slab of dead tree that has never slipped a jab, never shot a takedown, and consented in advance to the entire interaction. And, if it's too hard, we can just do some cuts on the board to make sure you don't hurt yourself too badly when breaking it. Splitting one proves you can hit a thing that agreed to be hit. We do not hand out belts to people who finally open a stubborn jar, and that jar at least puts up a fight.
The sparring, when it is finally permitted, is point sparring. Two people lunge in, tap each other on a chest pad, and recoil backward like they have been de-fibrillated while a man shouts a number. It is the only form of combat where the winning move is to make contact and then immediately flee the scene of the crime. You can become a national champion without ever once finding out what getting hit feels like.
And over all of it floats the mystique. The screaming, because somewhere it was decided that violence is more lethal when clearly narrated through screams. The sensei in a strip mall between a nail salon and a vape shop, awarding a black belt to a seven-year-old who cannot yet tie his own shoes properly but can absolutely register his hands as deadly weapons, a thing that has never been a law anywhere but keeps on being said. By the same people who warn you that they're a menace "when they start seeing red".
The footwork is real. When a karate guy actually walked into MMA and won, Machida, it was not the kata or the kiai, it was the distance, the timing, the in-and-out movement that nobody else was drilling as hard. Karate can work well. There is a genuine, sharp skill buried in all that ceremony. Karate's tragedy is not that it does not work. It is that it spent fifty years hiding the one part that does under a mountain of belts, boards, breathing and several degrees of McDojos. The most useful thing in karate is the thing it brings up least.