Excel was the product that really overwhelmed the competition--including Lotus 1-2-3--when the world transitioned to Windows. Word and Powerpoint were decent programs but there were plenty of competitive options out there. But getting Powerpoint and Word for "free" as part of a Microsoft bundle pretty much sealed the deal. (And arguably pretty much froze office suites in amber.)

I still use Excel all the time. Most of my work is digital signal processing, and I use the Complex number features in Excel for analysis.