One bothersome point ignored in the article is the problem of finger-smudges on the touchscreen.
While this is not much of an issue for user input displays, such as touch-keyboards, -menues, or -icons, it is a serious problem when the touchscreen is used also for output of text or images.
A dirty keyboard or mouse can be ignored; a dirty touch display is very aggravating.
Users will persist in eating while browsing; this almost unavoidably means the use of a pen (or chopstick?) for touchscreen input.