if your system dies, you need some way of restoring saves whether you use an mlc or usb with otp.bin or seeprom.bin and otp.bin (for usb) and dumpster U or something similar. you don't have to backup saves unless you want to. wii games and wii vc save to the same location. wii vc can't be changed afaik, but you can use emunand for the vwii. most games should support it. cube games can use memory card emulation, which is an option in nintendont. wiiu games can't be saved to sd card. they'll always be saved to the same partition that the game is on. wiiu would need an app to backup or ftp, but an app like savemii mod is much faster.