The introduction of the Bilingual Excel File Type was a huge leap forward!
But customers often require the translation in Excel to several languages, often including some translations already.
In this case either you create an individual project for each language with the bilingual file type or you solve it with the normal excel file type and need to copy/paste all the languages in to your target file.
It would be very timesaving to have an Multilingual Excel File Type for these cases.