I'm a long term enterprise user of Excel, and I taught myself to program using VB6 and have now moved onto Postgres/Python etc. For any serious data applicatio

I'm a long term enterprise user of Excel, and I taught myself to program using VB6 and have now moved onto Postgres/Python etc. For any serious data application, CSV is a must, because navigating data types in Excel is a nightmare. Over and over, colleagues of mine have lost the leading zero in a string because Excel automatically typed it as a number, or had a cell value interpreted as a formula, or had a VLOOKUP not work because the number is typed as a string or vice versa. These problems often have counterintuitive solutions, and for a basic user, these issues exist in both excel formats and in csv. Excel has pretty robust ODBC integration that drives data directly into Pivot Tables or through VBA. In this way you can provide informative (and pretty) reports to end users, with dynamic aggregations, filters etc. If your users are more technical than that or require more detailed atomic data, the widely compatible solution is generally csv. What I'm trying to say is that the excel format fills a gap that is very small, between completely non-technical and slightly technical data users, and honestly probably isn't worth implementing.