Punishment and reward are big parts of behaviorism, especially operant conditioning. You have reinforcements and punishments. A reinforcement is a reward, and a punishment is, well, a punishment. Both reinforcements and punishments can be positive or negative, that is, encouraging or discouraging a behavior.
For instance, I can give a kid a candy if it does when I tell it to stop or if it doesn't behave badly. In the former, the reward encourages the behavior of listening to my command, whilst, in the latter, it discourages behaving badly. I can also spank a child if they break the door slamming it or if they get bad grades. In the former, the spanking discourages the behavior of slamming the door, whilst, in the latter, it encourages the behavior of doing well in school.
Obviously, there are ethical concerns in some of those examples, but that's not the point. The point is to summarize operant conditioning.
As for the particular question, generally, I think that reinforcement is both more efficacious and ethical than punishment. It can just as effectively change the behavior, although it may take more time, effort, and creativity. In children, it teaches by example to be kind and compassionate, not cruel and authoritarian - a valuable lesson for any eventual adult. And it fosters a healthy relationship with the child built on love and respect, not fear. Ethically, it avoids completely any potential issues of child (though it may be more likely to lead to the spoiling of a child). And, more philosophically, punishment is a dangerous mindset of which habituation or normalization is be avoided for one's own well-being, moral character, and worldview.
I think there is never a good educational reason for beating a child.
Because that aggression will either cause passivity in the child or aggression towards others.
So most probably beating your child to a pulp on a daily basis is not gonna turn them into Nobel prize winners also I don’t understand how people think that hitting other adults is a no go but beating up a tiny toddler is okay. Obviously you shouldn’t hit other adults, but how do they think it’s fine for a child ten times smaller to endure who hasn’t even emotionally developed yet.
So if you beat a child it will often times happen the child will do the same to their child if they get overwhelmed.