Yes, I mean if prisoners want to choose to just die rather than spending their entire life in torture behind bars, they can. Basically this would be like a suicide option instead of the death penalty.

Most of the time people commit suicide because they just hate themselves and think others don't like them and are thinking that suicide will benefit others as well

Suicide is not always a selfish act because a person can commit suicide because they think that them not being alive will benefit someone else because of their wrongdoings to that person

I think murder is worse because even though suicide is heartbreaking to the person's family, at least suicide is an act of someone's own will and choosing. Murder on the other hand is just taking a life without anyone's consent not benefiting anyone and only making the murderer and the victim's family feel even worse. I mean if that's the case then some may say that murder with the victim's permission is okay, maybe.