Is there a particular benefit from not having the death penalty? No. It keeps criminals alive. In states that have the death penalty, the inmate has a much greater chance of dying on death row of old age than actually being put to death.
On the other hand, where the death penalty is not available, Richard Speck got big tits and Charlie Manson gets to update his website.
It just makes us look like barbarians to the rest of the world
If the death penalty is such a deterrent, why do we have such a high murder rate compared to other countries without a death penalty?
Because we have an inordinate number of people who enjoy killing others. Isn't a constitutional right to pursue happiness?