1- its shape is comfortable
2- the layout is dogshit
3- The shoulder 'buttons' are fascinating and an interesting concept in 2001 but fucking unbelievably impractical, loud, and dogshit in every conceivable way
4- Nintendo made a 1000Hz controller in 2001 and I noticed that games felt "higher fps" on the GCN despite running about the same back then so it made an impact for sure. They're so fuckin based for that. Shame the Switch/Switch 2 dont' have low latency as a priority at all.