Same as \csv2excel, \excel2csv is built on top of Aspose APIs directly.  There are a few cases that \excel2csv cannot handle at the moment, described below:

(1) \excel2csv may run out of heap space:

Similar to \csv2excel (described in item 2, issues #7486), \excel2csv will run out of memory if the input excel file contains too many rows.
On my desktop, reading an Excel 2007 file containing 500K rows generates the following error:
   •excel2csv: •'csv500K.xlsx': •conversion failed: Java heap space

(2) Pass an Excel 2003 file to \excel2csv with '-t 2007' option would generate this error:
   •excel2csv: •'standard input': •conversion failed: java.lang.NullPointerException

Examples:
   > cat csv1K.xls | excel2csv
   > cp csv1K.xls tmp.excel
   > excel2csv tmp.excel -t 2007

(3) Pass an Excel 2007 file to \excel2csv with '-t 2003' option would generate this error:
   •excel2csv: •'standard input': •conversion failed: This is not a structured storage file.

Examples:
   > cat csv1K.xlsx | excel2csv -t 2003
   > cp csv1K.xlsx tmp.excel
   > excel2csv tmp.excel -t 2003