Is it to punish Bad Guys, said punishment being a deterrent to keep all those not-quite Bad Guys from taking the plunge?
 Is it to protect the populace, keeping Bad Guys off the streets?
 Or is it to rehabilitate Bad Guys, transform them into Good Guys?
If it's  or , ditch the iPads and stack 'em up like cordwood. If it's , give 'em all iPads and teach 'em web design (the modern equivalent of making license plates), but don't call it 'prison,' because words mean something. It seems to me the justice system blurs all these distinctions into a muddy and costly mess.