Those cheap Wii wireless GameCube controllers

[K3Nv4]

Anyone know if they're worth buying or works well with USB loaders

CirKa "FreePad" Wireless Controller for GameCube (Black) https://a.co/d/aGnuJPH

 

[morning_glory]

At best, if you're lucky they'll work.
Looks like the same as I have. But, mine has issues. Minor, but still annoying.
Firstly, I find they work slightly better when you plug them in after you actually start the GC game/s.
Haven't really played with it too much, but I know you will be looking at the plug fit & wonder if it's sitting correctly.
Using extensions is mostly a failure (with wired types). 1 ext plays up & little less than 2 ext.
Most likely better to invest in a expensive wireless brand. Good luck.

ps. WiiMote will get you to your GC games, but then the other controller is needed.