> There's this entire train of reasoning that seems to be that a rich interface is one that places as many demands as possible on the human body I disagree com

> There's this entire train of reasoning that seems to be that a rich interface is one that places as many demands as possible on the human body I disagree completely. The line of reasoning is "what actions can we perform that have the highest bandwidth, and lowest cognitive load?" And various forms of manual manipulation, like gripping, are an excellent avenue of exploration when answering that question.