I used to spank. I don't anymore for a couple of reasons. My kids have reached an age where there are other more effective punishments and I no longer agree with it. Their behavior improved tremendously after I stopped spanking.
I don't think that all spankings are violent. I don't think any spanking actually teaches a child any type of problem solving or reason for a rule, etc.
I think that the purpose of spanking (all punishments in general actually) is to get a child to obey. I think the purpose of discipline is to teach a child to make wise choices on their own so that as they become adults they are self-disciplined. Therefore, I think that in many cases, punishment and discipline are counter to each other. At this point I would choose a punishment that was as close to a natural consequence of their behavior as possible so that they learn that consequences are not arbitrary. They are related to their behavior and will happen even if a "punisher" is not readily available to punish them.
Besides research about the connection between violence and spanked children, there is also evidence that when parents rely primarily on punishment as a means of discipline, what children learn most is to avoid the punisher. They avoid the person in general, they avoid them when they want to do something that would not be approved as opposed to avoiding the behavior that would lead to punishment, and they avoid being punished by lying, concealing, and using emotional distance. That is not the relationship I want fostered in my children.
I want them to see me as a guide. A person who can help them to figure out their own messes, who can help them to think through the consequences of an action, a person that can be trusted to teach them, not just punish them.
When my son was not turning in assignments he did lose screen time, but not as a "punishment" but as a portion of a time management activity. It served as a punishment, yes, but he saw the connection and understood that it was a lesson in responsibility. That is how I want things to be between myself and my children, and it works well for me.