Oh wow, just looked it up and the description is even better because it was intended to give the games mouse look controls, which IMO is superior to even dual stick for fps. Like set up a mouse and keyboard for a console fps that supports it and it's like easy mode because you can aim much more quickly.
Guessing you need to bring your own ROMs (I wonder if I can rip my GCN discs with a blueray reader). Though to clarify, is this for the GCN versions or one of the other ports/remasters? I've got 1 and 2 for GCN and 3 for Wii.