Yes, the full lock mode does his job: you can't access any app that would distract you. But people could still call you in case of an emergency, which is not the case if you just turn off your phone.
It activates fast. So fast that the app didn't give me the time to give it a permission it asked right at the moment I pushed the full lock mode. Could be interesting to put either a timer before it activate (like a minute) or to temporarily prevent the locking if the system is asking something.
Another problem is that a bug doesn't allow everything to go back to normal. My internet connection is good, there is no reason that even 3 hours later it doesn't go back to normal.
You can correct that by uninstalling the profile in the phone settings. But then it will throw all your apps together on the screens, destroying all your organization (and yes, I had installed the organizer, it just didn't work).
Because of my job, I have hundreds of apps on my phone. Having to spend an hour reorganizing them isn't exactly the best to fully get of of my phone.