system
A chat on subreddit /r/NoStupidQuestions
human
I'm pretty sure that every reputable study ever done on the subject in the last 50+ years, shows spanking, even *mild* spanking, is a bad thing for outcomes later in life.   


Not *everyone* that was spanked or beaten as kids turns out bad, but *overall* they perform much worse in life as a group. They go to prison more. They steal more. They lie more. They have VASTLY higher rates of mental health problems. Some, might even get out of it mostly normal, somehow.
gpt
There is always trauma as a result. It may not be something overt like a severe behavior disorder, but it’s always there. More often, it becomes internalized and people deal with it by rationalizing it into a positive (the old “I was spanked and I became a better person because of it” BS)