When moving from a mostly broken .xls data export system to a CSV file with the same data, we got lots of complaints from customers that it was too hard to use.
CSV files ARE broken in Excel. Have you ever tried importing a column of data with numbers that contain leading zeros / are not meant as numbers? There are at least 5 ways to do it wrong.
I know how to do this in LibreOffice (requires an extra step above and beyond double clicking) but honestly I do not know how to do it in Excel, and I would not attempt to learn or teach this knowledge to a person who does not have experience with a different spreadsheet tool first.
When moving from a mostly broken .xls data export system to a CSV file with the same data, we got lots of complaints from customers that it was too hard to use.