Nintendo has confirmed that the GameCube controller will work for other games on the Nintendo Switch outside of the Nintendo Classics range of GameCube titles for Nintendo Switch Online members. Obviously some games won’t function properly due to all the buttons and features some games require, but it’s nice to know it’s an option.
“The Nintendo GameCube controller is designed for use with the Nintendo GameCube – Nintendo Classics collection of games and is an optional way to play those games. Since it doesn’t have all the buttons and features found in other controllers that can be used with the Nintendo Switch 2 system, there may be some issues when playing other games. The Nintendo GameCube controller can only be used on Nintendo Switch 2 and is not compatible with Nintendo Switch.”

That’s cool. I haven’t heard anyone (whose gone hands on) talk about the d-pad on the joycons. People who are particular about their d-pads did not like the joycons for switch 1. I wonder if that is the case, how the procontroller’s d-pad is. Maybe GameCube will be preferable.
We know. Just like the others. Them not guaranteeing compatibility is standard on all of these controllers due to the amount of buttons and or the button layout. Compatibility is about more than “does it plug in”.