Why not leave me in prison then if we're certain I'm going to do it again? If the chance of me doing embezzlement is the same after I come out of prison than i

Why not leave me in prison then if we're certain I'm going to do it again? If the chance of me doing embezzlement is the same after I come out of prison than if I had never been to prison, what is the basis for caring whether or not someone has been to prison? This assumes a justice system that works, at least in the sense that if you commit a crime and get prosecuted, the following actions are sufficient to prevent or deter you from doing it again, which given things like plea deals, etc. is not. If we just want to reduce our justice system to a social credit verifier and background check database maintainer, or if this is really the best that can be dne, fine, let's admit that so we can try to do it a lot more cheaply than what we're doing now.