From Ars Technica :
https://arstechnica.com/gaming/2022/01/sony-confirms-playstation-2-vrs-specs-first-official-game/
"Eye tracking, meanwhile, is advertised primarily as a form of control, so that in-game elements like characters can respond directly to a user's gaze.
But Sony also mentions the technical benefits that eye tracking can bring, as part of a system known as "foveated rendering." With such a system in place, wherever a user's pupil isn't aimed, a VR system can dynamically add blur and reduce pixel count in a way that natural peripheral vision might not perceive. And with fewer pixels being rendered, VR software can run at the faster frame rates that the standard demands. Commercial VR headsets have very little in the way of formal foveated rendering systems, with only select HTC headsets employing the feature—and not in a way universally embraced by VR game developers. Having such an efficient standard on a popular platform like PlayStation, on the other hand, will likely accelerate its adoption."
Sony themselves confirmed PSVR 2 will use eye tracking foveated rendering... Of course it will also enable great stuff in gameplay, especially when interacting with characters.