With most touchpads/trackpads, you can tilt your finger by a few degrees in any direction to fine-tune your aim before you click. This enables pixel-perfect clicking when you need it. (Use the physical button when you do this, because tapping will ruin your aim.) With touchscreens, you can't fine-tune your aim before you tap. You just tap, and hope that you hit the correct coordinates.
And with most touch-screens you can (un)pinch to zoom in and get as accurate as you want/need.
The entire desire for 'pixel-perfect' clicking on a static UI is a symptom of trying to shoe-horn touch into interfaces not explicitly designed for it. Has that ever worked?
