Each buzz on my wrist or ding in my earphones that someone had written on my wall, or mentioned me in a tweet (let alone the non-social notifications: that your farm is ready for new crops, that your fantasy football team just lost the lead; that your apps have been updated) took me out of whatever I was doing, forcing me to trade focus and clarity for a tiny, hollow reassurance that I was up to date.
Since disabling them, I've felt calmer in my work and personal life. I've been able to focus on both actual tasks and actual leisure much more easily, as opposed to dropping out of them to check on my phone every ten or so minutes (at which point I inevitably get sucked into a different app or timesink.)
Maybe I'm just weird; maybe it's just a placebo thing. I dunno.
There are a number of reasons why this app may be helpful for you. But I urge you to ask yourself before downloading it: how important is it to you to know when the newest Verge article comes out? Is it really worth your time and attention?