Spreadsheet templates are used for many reasons and each template vary according to the purpose it is used for. Spreadsheets are designed with different calculations depending on various needs.
All of these things pull you away from the thing you really want to do...which is to build and sell great spreadsheets. The best thing to do is use Excelville.com since they have web developers and internet marketing specialists to help get exposure for your spreadsheet.
Undoubtedly, spreadsheets can help you improve the efficiency of your company regardless of the nature or size of your business. However, it is very important to note that the process of programming formulae and mathematical algorithms behind spreadsheet programs can be very complex and time consuming; one having to invest much effort to create the most appropriate spreadsheet solution for one's company.
You could make money doing something you love (or like [or maybe not so much but just really good at]). It's great to see a spreadsheet come together, and usually a lot better than what you originally envisioned. Especially when the dang thing works.