The big problem i foresee with AR is that frankly it needs to be always on to be effective.
But have you tried keeping a smartphone out of sleep for a day? You will be lucky if you get through a full work day without needing a charge. And thats on a device you can put down while doing something else.
It seems like the problem you are describing is battery life, not the use case of being always on.
You are correct though that AR is best when it's persistent. Consider though that for parts of the day (at work for example) you could plug it in while in use.
That depends on the type of work. AR at the desk is superfluous.
AR at the assembly line, on the shop floor, or any other job where standing and walking is done for most of the day is a very different thing. But then plugging in becomes a real problem.
That said, perhaps we will see some development in hot swapped batteries. I recall seeing a video some years back about a no-brand tablet someone found in a Chinese market. It was powered by two Nokia batteries that either to be hotswapped while the other remained in place.
Hardly. Maximize and customize your space how you like. You can literally change everything about it. For example, if you work in an open plan office, you can put a virtual divider up between you and the persons next to you temporarily so you can focus. You can also take your whole "desk" with you everywhere with the layout you like - like moving your laptop - except everything else comes with it.
But have you tried keeping a smartphone out of sleep for a day? You will be lucky if you get through a full work day without needing a charge. And thats on a device you can put down while doing something else.