As someone who tried Roku, Android TV, and Fire TV before switching, better hardware offers a vastly better experience. The Apple TV's hardware is fast. The UI doesn't lag. Things feel smooth as butter. Yes, maybe the Apple TV doesn't need more, but more can be helpful.

In terms of AV1 support, YouTube often only does 4K with AV1 so that's an issue for people.

Personally, I'd love to see an Apple TV that was great for gaming. New Apple processors have hardware ray tracing and decent gaming performance.

I think it's also likely that Apple will try and make an Apple TV that will support next-gen Siri and on-device AI stuff. Yes, you can complain about Apple's AI delays, but Apple's probably looking toward an Apple TV that can support their AI models.

In some ways, "what benefit would a new <insert-thing> have?" Sometimes we don't know until we have it and people start using it.