people with restricted IT skills and saving an Excel file as CSV will be beyond some of them

From my experience, those people with low IT skills don't even know that Excel can save in different formats, and so each and every file that opens in Excel is called an Excel file - CSV, XLS, XLSX, XLSM, and so on. Completely logical from their perspective, and a big mess when you are in IT or application support. But that is also an advantage. All they know is Excel and MS Office, and they don't have the slightest idea that things like OpenOffice / LibreOffice, KOffice or Gnumeric exist. Maybe some users with DOS experience still remember Lotus or Quattro Pro. So, it is very likely that almost all spreadsheet data comes in either as CSV or in one of the Excel formats.

Alexander