Night auditors are on high demand because these are individuals who are willing to work with less personnel and during hours of the work's journey when it is hard to find immediate support systems in case something goes wrong.
The night auditor is responsible for working with the night staff as a superintendent. They are also responsible for balancing the accounts at the end of the day, which is when the fiscal day ends in most businesses- often being right at midnight. The night auditor also has to serve as front desk attendant in some cases and, whenever there is a missing staff member, it is the night auditor who may have to step in and do those duties if necessary.
Along with having to balance budgets, checking the numbers, and acting in lieu of any missing employee, the night auditor may have to be on-call to fix any off issues that occur in the business in the middle of the night. This is why it is an important position; it requires a lot of responsibilities with often limited resources.