Well, yes, we did look into a solution like that. But like you said, the problem is getting reliable notifications, amongst others. You can sometimes get around that by using a 3rd party notifications provider, like OneSignal or Pushbullet, but those charge a fee for every notification sent. And that's assuming they've got a proper plugin for the platform you're using.
I think our solution is reliable (still needs a bit of work, but that's just server-side) and without reliable notifications an app like ours is next to useless.