If you SSH to a remote host and run Nautilus, it will load a GUI file-browser on the remote host. Unless this host is close by, you wont be able to use this to copy/move any files.
I use SSH all the time, both at command line (to distant hosts, over slow connection) and from Nautilus (on my own Ubuntu PC) using 'Connect to server ..' to open a new tab (or window) of the remote machine. This then allows me drag-and-drop, to/from local machine and remote machine.
Note: Nautilus works best in 'pull' mode, (that is) copying from the remote PC to your local PC. In 'push' mode (copying to a remote host) it will often replace file date-stamps (due to a Nautilus and/or SSH/SFTP bug) with today's time/date.