Every NAND is console-unique. It is encrypted using a per-console AES-128 key (the "NAND key") derived from the console’s private ECC keys. Without this key, a downloaded NAND file from another Wii is unusable without significant cracking.
Despite the technical difficulty, some users seek pre-dumped NANDs from websites or torrents. Motivations include:
The Wii has a built-in internet connection and a virtual store called the Wii Shop Channel. The store offers a wide range of games, including: