I used spreadsheet software all the time back then, and used it basically as an early InDesign. Change cell shapes (to pixel precision), add borders to parts of the cell but not others, add no borders to a group of cells to make a giant text box, etc. Main thing I designed back then was character sheets for ADnD, but I designed other things as well. And those character sheets were super elaborate for the time. I wouldn't qualify as the 'average user' though, granted.