That’s from this post by Alan Jacobs, commenting on an essay from the NYRB by Edward Mendelson. It seems like a good question to me, though I am not sure that so many people would find these scenarios so different. But, assuming that’s accurate, an obvious difference comes to mind: screens watch you back and paper doesn’t. The screen reader seems more vulnerable, and reminds us of our own vulnerability to the unseen watchers who have inserted themselves between us and our correspondents. There is a sense of helplessness, an inability to protect ourselves from exposure in the midst of wanting to sustain a private yet social life.
The “zombies” enthralled with phones perhaps seem subjugated by a device and by the industry that made it; people reading letters don’t appear to be in the helpless thrall of paper manufacturers.