Competitions are fine as a warming up exercise
but
Fight to defeat your opponent
physically
Not technically
Impossible to do this I'm afraid.
Karate is like using a firearm. You cannot use it on a living thing. But enthusiasts wanted to a) Practice shooting b) test their skill c) Compete against others (For FUN !) therefore they aim at targets.
Same with swords, Tameshigiri is practiced on Makiwara. (They don't even practice on condemned prisoners or bodies nowadays - It's called "Living in a civilised society" )