Excel (any MS-Office application) is used so widely in the enterprise environment that is is the standard format for sharing spreadsheet data between companies. There is often a need to repeatedly manipulate similar files as input, in exactly the same way several times a week even. I can save you anywhere from a few minutes to several days worth of repetitive data transformation, analysis and reporting, with a simple click. That is the power of the Microsoft's built-in integration with VBA (Visual Basic for Applications). This is not black-box arts or something to be feared. Simply saving time and money.