If I sign in with Apple and opt out of giving my email only to be faced with a prompt demanding I give up my email address, I'll be upset. I JUST told the app (via checking the box in Apple) that I don't want to give my mail, so why is it now suddenly required?

However if the app allows me to sign in and only asks for my email when I try to interact with a feature that would be more usable had I given my email, then I would be more accepting of it. Though I would still fully expect to be able to use the app in its entirety even if I opt out.

Now what Apple will say to this, I have no idea. But as a privacy conscious user, I would be happier with this.

As for having to come up with silly names, I don't understand why I need to be discoverable within an app. We have established social media and communication platforms, use them. Let me send a link to a friend to connect with them in your random app. I don't need to be able to add them within the dang app.