I'm not sure what the SOTA is currently but the Vision Pro has much better eye tracking that other systems I've used in the past. Idk if the sensors are actually better or if it's just the native integration into the OS and apps, but it feels more seamless than a mouse and I've never "misclicked" on the wrong thing with my eyes. It kinda feels like if the mouse cursor instantly jumped to the right place every time with no travel time or physical movements required.

I've used a 3D mouse for CAD but am not sure where else it would be helpful?

Tobii https://gaming.tobii.com/product/eye-tracker-5/ is standard in consumer eye tracking, they even have integration with some popular video games! There's just no value in it. I tried an older version in a store, and it was basically perfect, tracking my eye's movements exactly, with zero delay.

Nobody wants it for day to day computer interaction. Most people using eye tracking for computer interaction are disabled, because it's a terrible experience.