Separating the two bits like this lets you have your cake and eat it too; it allows for a causal explanation between a person's (comprising both their physical and non-physical) state, and their actions, but that total state (and therefore, responsibility) can't be completely reasoned about in the reality that we exist in. They appear indistinguishable from the 'uncertain decisions' you mention in your first post, but are (in the whole picture) simultaneously causal/responsibility-inducing, and completely inaccessible to some Laplace's Demon.

It's why this kind of system usually is accompanied by a whole meta-set of of punishments and rewards as well. Since there's no way to perfectly reason and judge in our system, we have to hope that someone who has access to the higher system will provide the correct judgement, being able to see the total picture of responsibility.

It's also completely untestable, for the very reasons it 'works' as an explanation at all!