Mozilla seems to be really concerned about Firefox users as it is continuously taking steps to provide a better experience. With the upcoming Firefox 72 that will start rolling out to users in January 2020, Firefox will reportedly hide popup notifications by default.
As you can see, the new implementation had a very minimal intrusion on the workflow since the only way I will get to know that a website is trying to show me notification is by that wiggly animated icon, which is far better than straight-up shouting at the user for permissions in my opinion.
Mozilla’s decision to hide the notification pop-up by default is indeed great for users. I personally disable notifications in browsers to avoid getting distracted when I’m looking for something. With this feature, I might actually consider keeping the notification popup feature turned on whenever I use Firefox as there is comparatively less intrusion.