I think the key term is direct manipulation.
There are two ways to look around something that is too big to fit in your fixed sight:
Moving surface, stationary eye
use reverse scrolling
Stationary surface, moving eye
- Hand scanner (remember those?!)
- Light pen
- Computer mouse
- Turtle graphics
use traditional scrolling.
Which of the two alternatives is a touchpad on a laptop supposed to simulate? Is a touchpad a moving surface or a stationary surface? You decide (that's what our Apple and Microsoft are empowering/burdening you to do).
To me the answer is obvious, but touchpads for laptop computers have been suffering from an identity crisis, not knowing which of the two above they purport to be. It's caused by tablets becoming the cool sexy young kid on the block and laptops trying to fit in for fear of being left out as the boring old one.
It is a failed experiment that needs to end. I have faith it will (considering how much more useful features have been discontinued by Mac OS). Or maybe we'll end up with laptops without keyboards (which would be another disaster that would set us back 5 years).