Well you feed them, house them, pay for the training, materials, managers etc, and then some corporations reaps the benefits.

Michael Jordan invested heavily in the prison system.

How big are the benefits for corporations and investors?

I don't know, but the business' is there.

Is it better for the inmates to work? Absolutely. But they should get paid competitive wages, eve if they can't access the funds.

But then that opens a whole lot of criminal enterprise....

Just thinking out loud friend lol