Is my life one iota better because there are prisons? No!
Oh, but you might claim I am "safer" when the bad guys are locked up where they can't hurt me. And I would scoff.
Prisons are nothing but concentration camps that enrich and empower the real bad guys.
Not all are as bad as this example, but none are good. And those who work in them should examine the evil they are supporting and enabling.
Prison, and the looming threat of prison, is used to silence legitimate dissent. A large percentage who are imprisoned are political prisoners- caged and controlled for violating drug "laws", gun "laws", and other counterfeit "laws". Some are caged and controlled for being uppity enough to do the right thing and defend their own life or property instead of standing aside while testosterone-jacked thugs who work for the State do the job (poorly and randomly) for them.
"Society", meaning individuals like you and me, would be safer if there were no prisons, and those who decide to attack or steal had to face targets who didn't have to worry that the legitimate act of self defense- of life or property- would result in a potential prison sentence.
Concentration camps are disgusting, and all associated with them would be ashamed if they had any ethics or principles.