I have to seriously question the accuracy of this study. I'm an obstetrician (cesarean surgeon) and I have never noticed texting to have a positive effect on my patients. From my observations, it seems to cause them a lot of stress (and thus increases the pain) and it almost certainly increases the duration of the procedure (because I'm busy texting and am just sort of jimmying the scalpel around with my other hand).
I had typed out a long reply explaining potential differences between your experience and the results of the study... then I reread your final parenthetical statement...
Somewhat OT, but I don't do pain well. Have asked to be knocked out 100% for oral surgeries. A few years back, I had no one to drive me, and the dentist wouldn't knock me out. I had some local anesthetic, and used my iphone most of the operation. "Oh this will be 20 minutes"... turned in to 90 minutes. I videoed several minutes of my operation (is "surgical selfies" a thing?) mostly to keep me distracted from the pain (yes, I still felt pain). Years later, the dentist still remembers me, even though I'm rarely there ("pink iphone, video the root canal!").
Strangely most people don't want to watch my root canal surgery. It's on picasa - perhaps I should put them on youtube...
I've noticed this about myself. Mental distraction helps with pain. Really useful when doing long distance backpacking and trying to push out the last few miles. I would whip out my phone and type into my journal.
I noticed this when I switched from a stationary bike at home (where I used to use my phone while riding) to a stationary bike at the gym where I just listen to podcasts. Actively using my phone was a much bigger distraction and made the rides seem a lot shorter.
I imagine it's a common theme of distraction lessens the perception of pain (including emotional pain), and most electronic devices - games, phones, etc - are incredibly distracting.
There are quite a few, and it's always the best option when possible. Most of the complications you hear about from "routine surgery" relate to the management of the patient's airway while they are sedated. An awake patient can maintain their airway.
While that is certainly not a good thing, it is not as dangerous as a situation where the patient is unable to breathe and the anesthetist is not able to breathe for them.