[soiler]

That is a significant part of it, but there's more to the problem.

Consider the simple task of looking up the definition of a word that you've been pondering. In pre-internet times, you'd physically have to move your body toward a specific room and seek a specific book. There may be a carnival, but even if you look that way and get distracted, you can reorient yourself and refocus on your goal by simply assessing your physical positioning and posture in space. "Ah yes, I am standing in this hallway facing east because that's where the library is."

On your phone, you pull it out of your pocket and unlock it. Probably the unlocking is not distracting on its own, but it's also quite possible that you've got some "useful" information on your lockscreen which can distract you immediately. Bad start, but let's pretend it doesn't happen.

Ok, now you're on your phone. There's a bunch of different apps, many of them actively trying to capture your attention - carnival-goers calling out to you to look at their show. Alright, distraction achieved - now tear yourself away and get back to your task. What was that task again? You see a bunch of apps, and you're curious about what's in them. And it would only take seconds to get a little bit of value from any of them - news, uplifting stories, comedy, whatever. Can context help? You're in the same place physically and emotionally that you are for most of your life, on your couch (or maybe in front of your actual computer). Nothing is different from the times when you are actually intentionally opening those apps. Oh well, it will come to you, just pass some time at the carnival...