Push Notifications must not be required for the app to function, and should not be used for advertising, promotions, or direct marketing purposes or to send sensitive personal or confidential information. http://bit.ly/2zcZnxP
52% of app users say that push notifications are an annoying distraction. This a problem that's going to be much harder to recover from. Remember, the reason why people mute notifications are because they're annoying.
Some marketers engage customers through other marketing mediums like SMS, emails, etc. But a web push notification is one of the effectively trending ways to attract the audience.