Exporting as "Excel" as a means of getting CSV is a dodgy hack.

• It means that exporting CSV is an operation that requires human intervention (ie. no automated services based off it)
• It requires MS Excel, which not everyone has (oocalc won't even open the file, instead passing it off to oowriter).
• It exposes one to the vagaries of spreadsheets. Try storing "2006-07-18 08:46:36.382085" in a text field. Excel and OpenOffice interpret it as a date, whether you like it or not, and lose precision when exporting as CSV. Spreadsheets could well break encoding when they interpret and save the contents.

JIRA should have a native "Export as CSV" option.