For copying files on the same machine you wouldn't need scpscp at all. Anyway, if you specify a directory or file as destination instead of a hostname and a path it will copy it for you locally, which seems to be what happened. If you supply the command line you used we can point you what happened exactly.
EDIT: With the supplied command line, what it does is to go over the network interface, connect to the SSHD server on your local machine and then make the copy. There is no good reason for that since you can copy it locally with cp.