It has extremely fine resolution... too fine, for most things. That's the problem... imagine you are trying to move your finger perfectly parallel to the desk, but 18 inches above it, to 'click'. Consider that selecting a tab on your browser means you have to be accurate within about 5mm up/down and 25mm right/left... and the imaginary plane you cross to 'click' is an inch long.
Maybe it'll get better with practice, but not so far.
Also, your arms get tired.
Maybe it'll get better with practice, but not so far.
Also, your arms get tired.