The reason I do think punishment is good for kid is because of my own experience. My brother who was older than me never got punished as a kid, he was the one who was spoiled. Myself and my sister and younger brother were mostly punish, I was canned at school, and I did deserve it, and I am today glade I was canned, I feel that I became a better person for it.
My older brother as he grew older was always in trouble with the police, and still my parents never disciplined him. By the time he was 14 he was in a boys home which he escaped, but was returned. When he got out of the boys home he got into trouble again, this time for rape, he was only 16 then.
He wanted a car so he told mum and dad that he would leave home if they didn't buy him one, which they did. Being to young to drive he got his friend to drive, on a Saturday afternoon the police came to our house to tell us the my brother was killed in an accident caused by their own selves, which was racing in the back streets where the car rolled and killing my brother.
This is why I feel the way I do about punishing kids who need it. Watching my parents go through life with guilt from buying him that car really stuffed me up. They became alcoholics and died young, I believe with a broken heart.