The demand for me to subscribe to notifications is 1000x more than my supply of time to attend to them.
I'm sure there are reasons notifications are useful. I like to get one when a 20 minute compilation is over or when something I posted to HN has dropped off the "new" page and won't compete with my next posting.
The fact though is I am already assaulted with spam, even reputable brands want to send me multiple emails a day even though there is no way I am going to engage them that frequently.