The way it's trivial for browsers to fake OS notifications on some platforms is a clear design flaw, though. I get the need for it (PWAs and such) but unless the website sending a notification is a PWA, there's no need for a notification to be that ambiguous.
The current system, where Chrome (the only browser that matters) collects information about websites and only shows the permission popup on some websites has mostly killed useful notification support for a lot of websites.