Desktop browsers don't have this limitation and I never have to play that game. It's just a stetting where you can choose to allow websites to ask for notification permission, or block it from every website.
Part of the problem for desktop browsers (except for power users) is that they've never opened the settings option, not once. They might have opened Mac's system preferences or Windows Settings app but other than that they have no idea they can toggle a plethora of options for their browser.
Check in with the average user of desktop browsers. You may find a lot of them have accidentally accepted web pushes and have no idea how to make them go away.
I'd be shocked if the vast majority of "use" of the "feature" weren't exactly that kind of spammy, unwanted messaging.
I dislike the desktop implementation of push permission request in macOS Safari
It presents a modal popup asking for permission. A few times I have accidentally clicked "Allow" only to have to hunt through my notification settings for the offending website to remove it
Web sites should not be allowed to present modal, native UI that can interrupt the browser. They should be contained to their window
A better implementation would be to allow the browser to show a bell or other icon in the main UI indicating the website offers push notifications. Clicking on that would inform and allow the user to opt-in
My desktop browsers get denied permission to show notifications at the OS level and are set to block them for all sites without asking.
I can't think of a single valid use case for them. There are only a handful of desktop apps (literally 4 or 5 apps like MeetingBar) that I allow to use notifications on desktop. For essential messaging app, etc. that I need notifications on, I configure them to be only on my phone, which I can just turn over if I don't want to see them.
This new iOS functionality therefore fits perfectly with how I use notifications: if I install the website like a mobile app, it can maybe get notifications, otherwise websites can't bother me even with requests to show them.
I do not want to have to go chasing “where did this annoying notification come from” game… ever.