Some people use them and some are very, VERY effective. Problem is, that's like for the 1% of what gets sent out. I've been working with iOS apps for 10 years

Some people use them and some are very, VERY effective. Problem is, that's like for the 1% of what gets sent out. I've been working with iOS apps for 10 years or so now, I've seen apps where push notifications alone drive 20%+ of the revenue, and other projects where the opt-out rate is ~90% with an open rate of ~10% (meaning literally 99% of users ignore the notification)