I used to work at in construction as an estimator and we used spreadsheets. No backups, no version control, a single value change took 10s of minutes to propagate through the many sheets in the file. We fixed errors when we saw them, but I always felt it was an exercise in pointlessness.

These were not small companies either, ~$800M in yearly revenue for one, and ~$150M for the other.

Then, afterwards, the end value would be massaged to what felt right. And yet, these sheets were seen as part of the "secret sauce" of the business.

It's one of the reasons I really wanted out.

Programmers have a reputation of being arrogant assholes, but I think this push-back and ridiculing other industries of using excel for stuff like this is completely justified. Excel spreadsheets let these people FEEL productive and like masters of their own fate with a bunch of numbers neatly encapsulated in their own little cells in a table, but their actual usefulness is questionable. For construction, it gives a rough feel for a project, but a lot of it is smoke and mirrors.