Answer:
Spreadsheets were among the first of the so-called "Killer applications". A killer application is one that is so useful it makes computers worth buying. VisiCalc was the first spreadsheet program, which was released in 1979. It helped to sell many computers. It was so popular that many other companies created their own spreadsheet programs. So spreadsheets became very important to the computer industry, helping to sell many computers and a lot of software, much like the internet does nowadays.