The most common case is overnight with a geographically distributed team.

How does that many notifications help? Isn’t it enough to see a ton of email and open an email client which does all of that aggregation for you?

Of course it doesn't, but Android already does the aggregation for me so that I don't miss important notifications from other apps. It's just a better way of working.

Again, it’s a question of degrees: you’re talking like this is a dealbreaker but it seems like more of an edge case.

I do think it, along with all the other ways iOS is deficient, is a deal breaker. I finally switched to Android after years on iPhone and I can't believe how much of an idiot I was for not switching earlier.

At least I wasn't enough of an idiot to use iMessage and get locked into the Apple ecosystem.

This runs contrary to Apple's philosophy. The user should not have to do anything.