In the context of HCI research, studies on air gestures have often emphasized benefits like speed and reduced physical burden.
This makes sense in the context of fitts law where we are measuring the time required to point at a target. For example, if we have a button on screen and the user is able to tap the button using air gestures, then the time it takes to hit that button would be slightly faster than tapping the actual screen. This is pretty similar to when the professor showed off vimium to the class where instead of navigating with a cursor, we navigate with the keyboard eliminating time to click a link or url.