Can you substitute self control with shiny apps like this? I don't mean that there isn't anything that can help avoiding distractions, but (from my own experiences) I have doubts about the effectiveness of soft measures like this. Dismissing a notification about going to sleep or taking a break in the middle of a youtube-binge doesn't require much effort, and investigating what takes all your free time takes significant energy. A commenter mentioned a cron job that shuts down his/her laptop at midnight - this measure can be more effective, because it requires effort to continue what you were doing, not to stop it.
Not to mention the irony of using apps to make you spend less time using apps.
Not to mention the irony of using apps to make you spend less time using apps.