There are three reasons to use a touchscreen for a UI: 1) minimal cost for a device that already has a display, e.g. e-book reader 2) reconfigurable UI for devi

There are three reasons to use a touchscreen for a UI: 1) minimal cost for a device that already has a display, e.g. e-book reader 2) reconfigurable UI for device that performs different tasks, e.g. smartphone 3) paging UI for vastly complex products that can’t accommodate thousands of different knobs, e.g. control panel for a non-professional audio generator. A car doesn’t fit any of these.