> I am moving my finger on my touchpad to move the pointer to more or less match what I am reading.

I do that too. I tend to "park" my cursor near where I am looking, or near where I anticipate clicking next.

> let's say that I want to login. My pointer is far away from the login link. My fingers are not on the touchpad. Is it faster to move my right hand towards myself, touch the touchpad, slide the pointer to the link or moving that very same index finger to the link and touch it?

Entirely depends on your relative proficiencies and preferences, I suppose.

When I had a touchscreen, I used it with a trackpad and a trackball. All three input devices had utility to me, so why not? These days I sometimes use a laser mouse rather than trackball, but same story (though my MacBook doesn't have touch now). I always prefer trackpad to scroll wheel for scrolling, for hopefully obvious reasons (range of motion and precision are both way better). I do know I got use out of the touchscreen even though I can't think of a hard rule for it. It's probably just nice to have on a case-by-case basis.