It is a very useful program; I use it on a daily basis to copy downloaded files to another directory. It's much easier to select files and move them with WC than it is to do it with explorer... And that's just *one* of the many things you can do with it.
(There's a multiple-file renaming tool in there, along with an ftp client, zip/rar/anything packer/unpacker, easy file splitting and combining, etc. etc.)