Why call it debt?#
Because each cause has a fix that does not involve a person, and paying it down lets agents do more safely. Until then the organisation pays interest on it in human attention, every time the same non-judgment reaches someone's queue.
How should the diagnostic be used?#
Ask "why was a person needed?" after the fact, honestly. Use it as a diagnostic, never as a target ratio. The moment a team is measured on reducing human interventions, the cheapest way to hit the target is to stop asking for review on things that genuinely need it.
Where the answer is that nothing in the system was missing and real judgment was exercised, that is not debt — that is the delegation boundary working.