Touch doesn't make as much sense on a desktop. It's more awkward because it is less ergonomic. If you put the screen lower so that your hand does not get tired you end up looking down too much, bad on your neck. If you keep the screen where it is in a traditional desktop you end up leaning over and your arm will get tired.
Touch makes sense in hand-helds and tablet style machines not desktop screens.
Touch makes sense in hand-helds and tablet style machines not desktop screens.