Batch Import API page saids that OpenCSV and Excel plug-in are not mandatory

Hello,

I try to install extension "Batch Import API" with Extension Manager:

1st try:
Resolving extension [Batch Import API 1.0] on namespace [wiki:xwiki]
Applying INSTALL for extension [Batch Import API 1.0] on namespace [wiki:xwiki]
Failed to get fields for class [org.xwiki.batchimport.internal.iterators.CSVImportFileIterator] because the class [Lau/com/bytecode/opencsv/CSVReader;] couldn't be found in the ClassLoader.

2nd try after manual installation of openCSV in WEB-INF/lib
Resolving extension [Batch Import API 1.0] on namespace [wiki:xwiki]
Applying INSTALL for extension [Batch Import API 1.0] on namespace [wiki:xwiki]
Failed to get fields for class [org.xwiki.batchimport.internal.iterators.ExcelImportFileIterator] because the class [com/xpn/xwiki/plugin/excel/ExcelPluginException] couldn't be found in the ClassLoader.

From extension page, I understand that Excel plug-in and OpenCSV are optional, from installation, it looks to be mandatory