Once we're start to use application, desktop notification becomes a part of our lives. By allowing the web app to display notification at the right screen corner, it's easier to keep track latest updates without having to open the app itself.
For communication a like Messenger or Viber, we even get the chance to reply instantly. Convenient, isn't it?
Sure, desktop notification is cool.
But receiving a request to extend your pornhub membership showing up during a meeting call doesn't sound so appropriate.