The game must have the same updates/DLC installed on the target Wii before restoring the save.
In the sixth and seventh generations of consoles, save files were typically considered passive data containers. However, the Wii’s architecture—particularly its use of encrypted save banners ( banner.bin ) and signed data blocks—allowed developers to issue post-release save file updates. These updates served three primary purposes: (1) preventing cheating via known save-game exploits, (2) adding downloadable content (DLC) flags, and (3) patching game progression bugs. wii save files updated
On the GameCube, a save file was just a raw block of data. If you had the right hardware, you could copy it, move it, and back it up with ease. The Wii, however, introduced . These were the .bin files users would export to an SD card. The game must have the same updates/DLC installed