I hope this makes sense... This is how the difference between cp and ftp was explained to me years ago...
Copy is a intranet utility where you have transfer files on the same platform... If you want to use the copy commands between different platforms, you need to use some kind of emulator application (Samba, Exceed, ViewNow)... FTP is an intranet/internet utility where you can transfer files across different platforms without the need of emulators.