Notifications? I need those from my calendar app and chat app.
Badges? Messaging systems I use rarely but which are important.
Visibility? I want resource intensive apps to "sleep" when not in use.
USB? I want an Arduino web ide to be able to communicate with hardware.
Screen lock? I don't want the machine to go into sleep mode when I'm presenting a slide deck.
Key lock? I don't want the browser intercepting keystrokes in my word processor or SSH session.