Z-Buffer 3D has a weaker 3D-effect then Geometry 3D, especially in the foreground of the scene. That’s the price for being twice as fast.
It works best in wide open spaces, for example in games like Skyrim or Crysis, where it can even look better than Geometry 3D in regard to overall scene depth. It’s not so great in smaller spaces where it can look a bit flat sometimes.
You can find a comparison between both methods here: https://www.vorpx.com/more-headtracking-z-buffer-vs-geometry-3d/
Hope that helps.