Spreadsheets are an incredible tool. They were a key innovation in the history of applications. I love them and use them.
But it's very hard to have a large conventional cell-formula spreadsheet that is correct. The programming model / UI are closely coupled, so it's hard to see what's going on once your sheet is above some fairly low complexity. And many workplaces have monstrous sheets that run important things, curated lovingly (?) for many years. I bet many or most of them have significant errors.
It's astounding how useful and intuitive they are, but my biggest gripe is how easy is for anyone to mess calculations, say, SUM(<RANGE>), by simply adding one row/column/cell.
I use Google Worksheets frequently to track new things that fit into lists/tables, and giving someone else editor access without them knowing a few worksheet nuances means I have to recheck and correct them every month or two.
This happened not so many years ago, in a certain small European nation, where official government housing valuation numbers were incorrect for some years due to a flaw in a spreadsheet.
I remember my apartment got a ~10% bump in value one year due to this flaw being fixed (fix didn't apply to all housing, just those who were on floors 5 or above).
I don't think though that a SaaS would have solved anything here.
But it's very hard to have a large conventional cell-formula spreadsheet that is correct. The programming model / UI are closely coupled, so it's hard to see what's going on once your sheet is above some fairly low complexity. And many workplaces have monstrous sheets that run important things, curated lovingly (?) for many years. I bet many or most of them have significant errors.