Remember, there is no cloud. It's just someone else's computer!
No matter what the server, if you make a 450 GB copy, it needs to go somewhere.
(As several suggested, using a downloader program would scan for a list of all the files on the server, and then would request them all one by one for download, so there would be no server-side copy. The "Archive" feature zips all the individual files into one large single file, and then downloads that one file, thus it does require a copy on the server.)