The homebrew community uses WBFS strictly for:
Raw ISOs contain a massive amount of "garbage data"—scratch data, duplicate sectors, and padding used to push the data to the outer edge of the disc for faster read speeds. Consequently, an ISO is always the maximum size of the disc, even if the actual game code is only 200 MB. nintendo wii roms wbfs
While standard WBFS is excellent, modern users often convert to or simply .wbfs files stored on a FAT32 drive. Today, the term "Nintendo Wii ROMs WBFS" generally refers to the scrubbed, compact file you store on a USB hard drive. The homebrew community uses WBFS strictly for: Raw