It's already pretty common for some sort of tool involving some sort of AI to collect receipt data and attempt to categorise them and hook up to your accounts. They also make mistakes, though the advantage of more tractable, less configurable and more limited models is they're unlikely to interpret a prompt as "invent receipts that have never been submitted" or "delete records", as well as trained much more on receipt OCR and less on poetry....

As a business, you've also got to remember that employees are much more likely to complain if the 'agent' or any other form of automation errs by denying their claim or underpaying than the reverse. Depending on the scale of expenses and how likely you are to be audited, the cost of the odd mistake might be more or less than the cost of doing it manually.