If you're a retributivist, you believe the point of prison is to punish the guilty. Therefore you will be uncomfortable with the idea of prison as a means to "improve society or economics".
Kant:
> [Punishment] can never be inflicted merely as a means to promote some other good for the criminal himself or for civil society. It must always be inflicted upon him only because he has committed a crime. For a human being can never be treated merely as a means to the purposes of another or be put among the objects of rights to things
And the country we're talking about is run by retributivists, and even further, whatever that is called - people who just want to see other people punished.
But if I’m a retributivist, why do I want to be less efficient with money and also make MY life worse, just to inflict more punishment on some prisoner? That just genuinely makes no sense. I can understand the logic of wanting to punish them for the sake of it, but I would also want to be efficient about it, and not make my life worse in the process.
You don't want to be "less efficient with money" or "make your life worse". Factors like that don't come into it. Neither does "making society better," "reforming the guilty party," or deterrence. And "inflicting more punishment" isn't the goal either -- that's just cruelty.
The basic point is simple. If a person commits a crime, they should be punished in proportion to the crime. Full stop. Within that simple framework, efficiency is fine, but it shouldn't be the goal.
Kant:
> [Punishment] can never be inflicted merely as a means to promote some other good for the criminal himself or for civil society. It must always be inflicted upon him only because he has committed a crime. For a human being can never be treated merely as a means to the purposes of another or be put among the objects of rights to things