If you have a backup of a game you bought and want to run it directly from the System Menu without inserting a disc or re-downloading.
Homebrew WADs (free, original applications) are completely legal. wii wads
Here’s a sample forum-style post for someone looking into (common in Wii modding communities like GBAtemp, Reddit’s r/WiiHacks, or WiiHomebrew): If you have a backup of a game
WADs are encrypted and signed with Nintendo’s private key. The Wii will only install a WAD if its signature matches the official Nintendo signature, unless the console has been modified with custom firmware (like cIOS or a patched IOS) that bypasses signature checks. The Wii will only install a WAD if
"Wii WADs" refer to files used on the Nintendo Wii console. WAD stands for "Wireless Application Download" or sometimes just "Wii Application Data". These files contain data for channels and applications that are downloaded through the Wii Shop Channel. When you download something from the Wii Shop, it comes to your Wii as a WAD file and is then installed.
Downloading a Wii WAD from a website is copyright infringement if you do not own the original game. However, dumping your own purchased Virtual Console games to WAD files is generally considered legal under fair use (as a backup).