. After 20 minutes of watching green blocks fill the screen, they have two precious files on their SD card: (the data) and (the "skeleton key" unique to their specific console). The Conflict: A Lost Backup
There is exactly one scenario where "downloading" a NAND backup is acceptable: Wii Nand Backup Download
A valid backup requires both nand.bin (the data) and keys.bin (the unique decryption keys). Legality and Risks BootMii Backup | Wii Hacks Guide Wii Nand Backup Download