I have a background in finance, and I think everyone is missing the problem that this is trying to solve.
People are careless when they claim expenses. They claim for things they lost the receipt for and then they try and pressure some accounts clerk into forcing it through. They make careless mistakes like multiplying their milage by the wrong rate, because they don't see why they should have to look up the right one. Then their line manager doesn't get around to signing it off, so employee chases accounts team, and accounts team have to chase approvers. Senior people are usually worst.
The accounts team then hand to justify why they processed a claim despite x,y and z...to external auditors.
Setting an expectation that if you don't get it right up front, the computer won't let you through is a very powerful selling point to a CFO who has to control this rubbish