The economic point of AI decision systems is that they can make an automated decision for $0.0001 of computer time, instead of $10 for a few minutes of an expert's time. For something like spam filtering, you obviously need the cheap solution. But you don't need that for the social interventions where you're making a decision about parole or something. You can spend $10 (or $1000) of people's time to make those decisions, because both their volume and impact is at human scale.