I installed this in the morning to give it a test drive, and after several hours, I learned the following: it's great when I reach for the phone as a distraction; it's a big annoyance otherwise.

E.g. each time I want to change the currently playing song, what was muscle memory gets scrambled by the interruption. Or, when I'm taking a lot of photos (like on my daughter's kindergarten event today), I tend to keep the screen off in between, and rely on being able to turn it on and shoot a photo in less than two seconds, total. Guess how that got screwed up by this app.

The app itself is great, and I'm still a believer in the concept of managing executive function issues by throwing obstacles in front of bad habits and known focus black holes. However, this experience made me discover the third class of phone activity, next to "distraction" and "work" - quick, intermittent, on-the-fly use, the kind you ideally don't think much about. This class does not distract you... unless someone adds friction to it.

I just saw the app has "every N unlocks" option, I'll try it out and see if this helps with the "third class".