After we die no one knows where we go. In fact, Whoever is being put to death could be anywhere after they die. If we put them in a dirty, Rotting prison that will be much more useful to prove your point, And will be certain to keep criminals away.
Additionally, We can use them for hard labor and other things that normal people are being forced to do. It will put them to work instead of being lazy all day.
Capital punishment demonstrates a peoples values towards freedom, Justice, And equality. Quite frankly, If you don't demonstrate this, Both to the criminal and to the rest of the population, Then you are conceding the moral high ground in a position that once warranted it. Its a showing of fortitude. I need to believe that my country cares about me, Cares about the things I care about, And believes strongly that if a person wrongs me that they will have my back. I make a social contract with them everyday, That I will not commit such acts because I recognize that the golden rule is in effect. The day you guys tell me that you aren't going to back me up when someone comes to take away my freedom, My life, Thats the day we all revert back to every man for himself. What incentive do I have to treat any of you with respect if you guys can't even come to respect me as a victim of a crime enough to hold the other guy accountable? Total breakdown of society, And over what? A guy who already doesnt hold you all in high enough regard to keep himself from killing you, Or me, Or whoever.
Then theres the monetary reasons. If the hole has been dug too deep for them to ever repay their debt to society, Cutting the cord is the humane thing to do for everyone involved. I don't know why its the criminal who is at the forefront of everyones worries when it comes to sentencing, But there is a burden being paid by the entire country at that moment. One of the parties broke the law and now the other 320 million are going to pay for it? For consecutive life sentences? How ridiculous is that really? Next time people need to think about all the other people they are damaging by keeping the guy alive. The prison system aint cheap, And recidivism is a priceless considering you could have stopped it.