One of the statements I see a lot is that mouseless, keyboard only HCI is faster. But as far as I know, to the extent that any real studies have been done at all, this assertion is false.
I don't have the references at hand but I think people like Alan Kay and designers at Apple would think it crazy to even suggest that a keyboard only HCI is more efficient.
Could You please add a single example for faster solutions to modify several (text/source) files' contents at once with mouse and/or touchpad mainly (or any other already existing HCI interface)?
Who said anything about a mouse and or touchpad mainly? As far as I know, the studies were for keyboard and mouse in combination and actually predated touchpads.
I don't have the references at hand but I think people like Alan Kay and designers at Apple would think it crazy to even suggest that a keyboard only HCI is more efficient.