When we review current human computer interactions, we find fingers/hands is used for almost every input – commanding, texting, and pointing.
Fingers are overloaded. However seeing is faster than finger to point in 3D, speaking is faster than finger in texting. Fingers are used for commanding (menu/icon selection, etc). But the operations are rather verey simple ones.
On the other hand, fingers are very dexterious. Fingers can manupilate pens, chop sticks, scissors, chisels, etc. Current human computer interaction has not taken the advantage of this dexterity. We could image future robot/machine work with the dexterious fingers.
At this moment, fingers have a big miss-match between its power and the usage in human machine interaction.
I added this obsevation in http://www.slideshare.net/Hagezaru/human-receptors-effectors-and-human-machine-interactions.