I agree with this. When you get to a certain size, while fingers work, pens are much better because the system will placed on a table. Fingers on a touchscreen of certain size will probably stick within the kiosk realm, or game. You can do some typing, but you're largely looking down.

A very large touchscreen PC with sufficient horsepower could be good for drafting, autocad, or maybe solidworks. Things of that nature where you're designing and creating.