WBFS was a specialized file system that "scrubbed" the useless padding data from a Wii disc image, dramatically reducing its size and improving load speeds by loading only the essential game data. While innovative, early WBFS had major drawbacks: it required a dedicated hard drive partition and was not readable by Windows. The homebrew community eventually evolved past the need for a special partition, and the standard became storing the actual .wbfs (the scrubbed game data) on a standard FAT32 or NTFS drive.
When dealing with "Wii games ROMs WBFS," you will encounter several file types, each serving a different purpose. It's also crucial to note that WBFS does not employ "compression" in the traditional sense, where a video file shrinks and must be decompressed. Instead, it uses a method called "scrubbing," where it removes the useless, pre-set "garbage" filler data (like blank 0x00 or 0xFF patterns) that padded the original ISO to fill a disc, leaving only the real game data intact. This ensures the game is exactly the same, just without the empty space, and you can convert it back to a full-size ISO at any time. wii games roms wbfs