When I soft-launched MVP I built to 50 odd users, I was surprised that one user said they uninstalled the app after a couple of days because they simply didn't like the app throwing nagging notifications (it seemed to me, given the nature of the app, the notifications were essential information, but apparently not). Android does let you turn off the notifications per channel per app, but I guess most users aren't aware, surprisingly, even the ones who are annoyed by notifications.

So instead of getting a permission prompt on load, I will get it when I first click on something. No thanks.

No. It should be done the way like Slack does it: - You want to get Notifications for Messages? Click here

So that you actually know what it's used for

I'm dealing with a bug currently where Slack doesn't keep track of whether I've enabled notifications, so I always get the banner. I think I'd go mad if every website did that :(

Not if you close Tab before clicking :)

There's the middle ground where I can freely browse the page without ever being prompted so see notifications. Apple gets this right.