Its a mouse, so you can maneuver it on a mouse pad rather than moving your finger.
Its a touch pad, so you dont have buttons that produce annoying clicking noise. You left "click" by tapping on the left region, right "click" by tapping on the right region.
I have seen some touch mice from big brands (Apple, Microsoft, Logitech), they are cheating by having a hidden button inside, which still produce annoying clicking noise.
Want to know if we ever have an input device like I have described and if we dont, whats would be the reason? Hard to use? Difficult to make? Not popular?