I disagree. I have seen many such Excel applications in many companies, paticularly in the finance and controlling departments that were delivering key numbers to the C-class which would never have allowed the sheets, applications or calculations out of the house, let alone to a cloud service or an out-of-company consultant/programmer. There were always backups managed by the department themselves and in one case, even entry to the room with the relevant machine was restricted to authorised personnel only. If I have learned anything in my 30 years of consulting, it's that you always take Finance at its word when they tell you No to your SaaS or ERP solution.