While I agree that dedicated devices can be more efficient than Windows-style user interfaces, and even more so than browser-based user interfaces, many people don't use those modern interfaces in efficient ways.

I have observed countless times how many people fill in a field, than move their hand to the mouse to move the focus to the next field or button, than move their hand back to the keyboard, instead of just pressing tab to move the focus. It's painful to watch. Knowing just a few keyboard shortcuts makes filling in forms so much faster.

Things are getting worse, unfortunately. Modern user interfaces, especially in web interfaces, are made by people who have no idea about those efficient ways of using them, and are starting to make it more and more difficult to use any other method than keyboard -> mouse -> keyboard -> mouse -> ... . Tab and shift-tab often don't work, or don't work right. You can't expand comboboxes with F4, only the mouse. You can't type dates, but have to painstakingly select all the parts in inefficient pickers. You can't toggle options with the spacebar. You can't commit with enter or cancel with esc.