This does look interesting, but I'd say it's not for every parent.
I remember when, as a first-time parent, our baby daughter was born. The first few days, when she was asleep in a cot in our bedroom, I'd listen to her breathing - I even got out of bed once or twice to check! That's how nervous new parents are.
But then you learn that she's not (thankfully) going to die in her sleep, so you relax. And whilst you do still care for, and watch over your baby, you learn to give her (or him) space when it's needed.
So, in my experience, there's really no need for this app beyond those first few, nervous weeks. Beyond that, you learn to relax a little as a parent. This is true of both fathers and mothers, in my/our experience.
I do think I would've used this app for maybe a month to 6 weeks, but not beyond that. Of course, all parents are different, and for really nervous parents they may use it longer...but shouldn't rely on it long-term (it's not healthy for them, as parents, or their child).
Nice hunting.