Brilliant Minds also had an episode where a kid had this.

Capital punishment will always be more of a tool to control behavior than a tool to regulate public justice.

A death penalty serves the ultimate purpose of demonstrating that the state can use its power (executive, legislative, and judicial) to order a citizen killed.

The power of the state to kill someone can be wielded arbitrarily based upon laws enacted (legislative), sentences ordered (judicial), and pardons withheld (executive).

Expect more laws and more capital sentences to curb more behaviors that the state wishes to curtail. When they run out of behaviors, expect capital punishment for crimes of belief, thought, and group affiliation for that is the natural progression of authoritarianism, despotism, and tyranny.