All kinds of operational departments. I'm sure it was used for accounting, payroll and commissions, inventory tracking, I know that teachers used it for gradebooks as I helped set them up when I was in high school (early 1980s).

Pretty much anything that you used to do on paper with a columnar notebook or worksheet and a calculator, or anything that could be represented in tabular form could probably be implemented in VisiCalc, Lotus 123, and others. Spreadsheets are probably the most successful software application that was ever invented. Certainly one of the most.