I have PS4 that I use it also for Netflix but I'm only wondering if Apple TV provides extra features to Netflix experience.
Really, the only difference is that the UI (User Interface) will be different between the Apple TV and the PS4. UI is the arrangement of any virtual objects that the user interacts with, so virtual buttons, menus, etc. will vary from platform to platform. Honestly, if you want to use it JUST for Netflix, what you have is probably fine, at least not worth spending an extra $69 over.
However, Apple is rumoured to unveil a new Apple TV very soon, which could have new features like a touchscreen remote, 4K support, a dedicated App Store, and more. So at least wait until Wednesday to make your final decision.
You can read all all the rumours about a new Apple TV here.
And watch the Keynote on Wednesday, September 9 at 12 PM CDT here.