It's hard to imagine quickly centering onto a headshot pixel (or group of maybe 12 pixels) with a trackpad. Especially if the target is moving.
I'd like to see a video of someone demonstrating real in-game use of these trackpads on different types of games. None of the reviews I've seen so far go into any detail on it.
EDIT: I found the trackpad usage detail I was looking for. But it's not using the new controller, just a steam deck. Looks a lot more accurate than I imagined. https://youtu.be/0BQEg3puMsc