I think the joke is twofold. First of all, Microsoft pretty much has a monopoly on financial software with their excel, which shows that the entire global finances are in the hands of that crab.
The second joke, must be that they never bother updating the suite to the latest, and solely depend on 2013🤷
Not just financial documentation, but everything. Planning staff levels, work assignments, quarterly reports, bonus calculations, pto administration, and more. There's likely people retiring that wrote an excel macro 20 years ago that still part of a critical business process.
For certain values of "works". I also think the learning curve is part of the issue. You end up doing stuff Excel has no business handling but is there due to the absurd scope-creep.