I have enabled web push notifications for a few sites, specifically Slack and Help Lightning. But those are both communication tools where I often use a browser instead of a native app and want immediate message notifications.
I have never, nor would I ever enable web push notifications for any sort of marketing or newsletters. I am still a huge RSS reader fan, and use imapfilter to automatically format and send certain emails directly to my RSS service (freshrss) [1].
I am big on zero-inbox, so I _hate_ having non important stuff in there. But for some reason, having a backlog of RSS feeds doesn't bother me! I wonder if part of it is that I find mobile email clients and web email clients so limiting when it comes to filtering and managing messages/threads.
[1] https://blog.line72.net/2021/12/23/converting-bandcamp-email...