How about expenses for directors/VP/Executive VP/CxO? Does this AI look over their expense reports, too? I would guess that even legit expenses from that level look a bit odd, but having AI audit employee expenses but not management expenses could contribute to a morale problem.
Another place that this AI oversight could help society as a whole is having corporations/companies get audited for wage theft. Wage theft is supposedly the largest dollar amount of theft in the US, and it probably exists because audits are so seldom done. AI wage theft audits could have a large beneficial effect for employees.