Debugging can be hard. That's often because what they're used for is done very fast. So, there's a business expert reasonably IT literature that has a powerful tool with a built-in IDE that doesn't take approvals or hiring requisitions or even budget and a problem's solved within a week on what otherwise would be a month (being kind).

The problem starts when whatever frankensheetvbasharepointdb is now an engrained part of a workflow, excelbizdev has disappeared, and 'maintenance' falls to nonexcelwhizz, or perhaps worse, a dev team that lacks much legacy business understanding to figure out why the particular implementation was done, screws up understanding, and creates something worse.