As a user who knows how to use email, I want to avoid 50 "Gilles added a project" notifications to ever land https://phabricator.wikimedia.org/notification/ in the first place, without giving up email notifications.
I'm interested in project notifications in general and I'm ready to use my email client to filter them, as well as to delete notifications in bulk by means of selection and "del" key in my email client, while the web interface has a lower level of functionality (cf. T75745 for the web interface).