"They use Excel for everything, regardless of whether it is the most suitable tool for the job."
Second only behind Salespeople for tracking (basically) everything.
That said when people look back on the history of computing I think they will find the spreadsheet was a more fundamental improvement than the word processor.
Historically people in large organizations had ways to produce high quality documents with good layouts. What was much less common was being able to generate quick "what if" calculations or models. Basically there was no mathematical equivalent to the electric typewriter.
Spreadsheets didn't just do this, they created a paradigm for structuring those problems into pieces that you didn't have to think about. Calculation on demand. When you want it, how you want it.