If you're targeting Excel and generate CSV, then use UTF-8 with signature and include the sep= line at the start. Joel mentioned it as an alternative to creating Excel files, i.e., creating a file specifically for Excel to read. If that's the goal you don't need to care for other CSV readers and simply make things nice in Excel.

SAP probably cannot do that.

SAP can do that, but the idea is to have standard support.

And that means that any program reading or writing CSV should support all possible standard-compliant CSV files.

You might get a CSV file from someone who created it with German Excel and want to read it into French Excel (it won’t work).