I don't think its even that rare.

As an example, there's a popular idle game called "ngu idle", full of complex overlapping and intertwined progression systems.

Someone made this spreadsheet to help you optimize your play. Some of the worksheets in this have very carefully considered UI and complex data flows. Its totally inscrutable if you've never played the game, but its more complex and well crafted than many apps on my phone:

https://docs.google.com/spreadsheets/d/1S1JXe3kZeqzxBOVXMo2-...

I once seen one used in risk evaluation for line of credits

Some people I work with have made very complex Excel "machines" that have been in use by many people for decades. One of the new engineers spent about six months porting one over to MATLAB and there were all kinds of magic numbers in the formulas that turns out were there to account for some bugs in some test equipment we bought 20 years ago. We had purchased a new system that would output data that wasn't compatible with his old model so the new engineer ported it over and now we get clean, consistent results. This is for antenna measurements so there's really been little advances in decades in the fields. The advances only really exist for antenna simulations.

The backbone of many statistical institutions such as the Office for National Statistics is Excel. I worked on porting a lot of complex Excel systems to Python that had been around for 5+ years.

There were teams of people whose job it was to produce one report over a timeframe and they had the process to a fine art.

The main problem came when members of said teams left. Macros locked behind passwords, magic numbers in formulas, the wheels could come off very fast.

If Excel had a more robust functionality for versioning and documentation it could be even more of a powerhouse than it already is.

@saberdancer: "When I saw this, I was blown away."

I've seen something like that, that took a whole weekend to produce a report. I suppose it does the job, as long as the accountant doesn't mistake 30 for 0.03 (30%) in a formula.

You've ironically made the same mistake yourself :D

The joke in the aviation industry is "Which enterprise software runs the most airlines?.. And the punch line is Excel.

I’ve worked with a bunch of huge Fortune 1000 companies that do similar things. Model each contract in its own excel file then every month put in that month’s data and have the excel model spit out how much you owe in the form of a formatted invoice.

Long time ago I found myself as the sole point of contact between 200 managers+workers office & regional HR office. I had recently came across excel, so made a simple sheet with names & staff numbers. That sheet, over the time of 3 years, evolved into a mammoth of sheet. sheet with db_ prefix listed names, joining date, title, salary, timebase, country of origin, skills, driving license number, expiry & many such. Other sheets pull up some columns, & I manually add D for day shift in date column, or N for night, H for holiday, F for Friday. Another one pulls this data per week for D only or N only or both. Another one pulls data & prefills the leave request sheet for individual staff. At any time I change the dropdown week value, & I can print a summary of man hours, who worked, how much expenses on HR. No where in the sheet I used VBA because of that macro dialog box.