only needed the .cue ?
Do you really thing your game is few Kb ? not 650MB?
The game is the ".bin" file, not the other one.
The .Cue file is a dump/burn data file, it can be used if the iso has multiple tracks (like tombraider dumped track by track with data+cda instead of Disc at once iso).
I don't remember if Wiisx use it to load multitrack bin files, but just keep them in the same folder, it won't harm to have more files.