mongoimport allows for import of formats such as JSON,CSV or TSV.While the user can convert their excel file to .csv and import,I am thinking, though .csv maybe a more flexiable data format for data exchange than .xlsx; their maybe more flat files in .xlsx format.Allowing mongoimport to accept these formats and possibly convert it to .csv and import the data into a collection may save the users of mongoDB an additional step when working with those files.