Notification Centre on macOS is a feature that's confused me for a while and one that I think wastes a lot of it's potential primarily because I don't think its anywhere as convenient as its counterpart on iOS.
I would guess that it's down to the interaction needed to use it. On an iOS device, you can see your notifications on the Lock Screen and can swipe up to reveal the full Notification Centre. But on macOS, it's hidden behind the date and time in the menu bar. So it's certainly not as visible or accessible.
This hidden nature leads me to hardly ever use it. So when I do open it up, it's full of old notifications that I need to clear out.
There's also the fact that notifications in Big Sur are plain dumb. If you've used Big Sur, then I'm sure you understand. I don't think I need to go any deeper.
But in general, I think that notifications on macOS could be a super helpful feature. It just needs to be brought out of the shadows. It needs to be accessible, and actions should be able to be accomplished with a single click or swipe.