It’s a novelty. Hardware hackers have been making smaller and more portable Wiis for years, finding more parts of the motherboard they can cut off, ways to rearrange mobo parts and reconnect them without impacting functionality, discrete parts they can replace with more modern smaller equivalents, etc.

This represents the smallest they’ve been able to cut down Wii hardware, still have it be functional, and still have the core be the original hardware, not a general use CPU with an emulation solution running over top. It’s not a commercial product meant to compete with emulators on existing portable devices like phones and SBCs.