This is an excellent answer. Let me add another data point for item 2. I know of several companies which have passed their ISO certifications or audits in no small part because of certain formulas in certain Excel workbooks.
If you are not familiar with ISO Certifications, this is a Big Deal. If you are familiar with Excel, this is mind-blowing.
Not sure which part you mean, but the important bit for this thread is that even basic Excel formulas are black magic to non-techies, and that basic hacking skills can drive real business value. There are things you can do rather trivially, such as "Add 3 calendar months to this date, and if it's later than this other cell, color the cell red," which would be a) extremely helpful, and b) otherwise a task they'd have to hire an intern to calculate each week, for many companies in the $1-20 million a year range.
And this is just Excel formulas, let alone the ability to write some VBA that does calculations and draws a chart, or a script with a regex that cleans data files, or a basic app for data entry...
If it was the ISO certification you were interested in, there are many certifications related to manufacturing, food & drug, etc. These certify that your company meets various standards, regulations, quality procedures, documentation policies, tolerance assurances, etc. These can result in a ton of additional business, since many customers desire or require them, and losing them is also a big deal. The certifiers audit companies regularly, and having some pretty spreadsheets that show how you are continuously improving and ensuring your adherence to the regs can be very valuable!
If you are not familiar with ISO Certifications, this is a Big Deal. If you are familiar with Excel, this is mind-blowing.