The way I see it, AVP wouldn't have to have some sort of special "killer app" or any kind of unique feature for it to be a hit.
However, what it would absolutely need is to be able to almost or entirely replace the average persons needs in a portable computing device, like an iPad or (even better) a MacBook.
Since humans still are typing on keyboards, and nothing is as efficient and precise as the physical ones, AVP has to have a virtual keyboard that is a 1/1 replacement for a physical keyboard.
The same goes for a computer mouse. But current AVP eye tracking seems to be accurate enough (verdict is still out).
Being on the go and just slipping on some vr/ar goggles and then being able to type and edit away "in the air" on a huge, move the "cursor" with your eyes, all on a high quality virtual display, but not lacking the precision or speed that you'd get on a physical keyboard/trackpad/touch screen is something that a lot of people would want.
That would make AVP a hit. Nothing more is needed.
Sales would then increase as newer models get sleeker, better battery life, and weigh less.