Death penalty? A punishment? How?

Should you rape a rapist? I surely think that that would teach a rapist a lesson.
Should you steal from a thief? I believe so.
Should you set an arsonist on fire? As long as they do not die; they should suffer.
However, I most definitely DO NOT agree the death "penalty" should serve as punishment for murderers. A punishment in its denotative meaning is defined as suffering, pain, or loss that serves as retribution or severe, rough, or disastrous treatment. How does a person suffer if they are deceased? Simply put..........they don't. My conviction strongly lies that any person that has inflicted pain on families and friends by murdering someone else should suffer in confinement. In other words, the death "penalty" is not a "penalty" at all. Millions and billions of Americans' hard earned dollars are frivolously being used or spent on a method of punishment that serves no significant purpose or purpose at all, for that matter. These killers, murders, and criminals are getting off easy. They are not enduring any type of anguish for their wrongdoings. In fact, the country and all those who bear the wrath of these evil persons are emotionally and financially wounded by death "penalty". Thus, does execution serve or constitute as cruel and unusual punishment? Of course not. It is not castigation, discipline, confinement, or anything pertaining to punishment. In modest terms, the death "penalty" is inconsequential and illogical.