I'll try to argue that most of these don't benefit much from a wearable HUD. Maps and navigation seem to be good enough when they are handheld or mounted on a

I'll try to argue that most of these don't benefit much from a wearable HUD. Maps and navigation seem to be good enough when they are handheld or mounted on a vehicle. When you are on foot you're moving slowly so no need to have it always visible. Yes, there's a special case of you're on foot and carrying two heavy bags in both hands, in an unfamiliar place outdoors, and cannot stop, and do not speak local language. Voice navigation should still suffice. Video instructions. Some of them have to be seen in advance to be able to plan your actions and logistics (e.g. cooking). Some of them teach skills which should be watched multiple times and/or tried multiple times to achieve mastery (e.g. sports and dancing techniques). What kind of instructional video benefits from being seen while doing, in real time? Even origami howtos are usually back and forth, until you _understand_ what you're doing. Not holding books in your hands. I admit I wanted it on several occasions. My concern is usability. Is it easy to read four hours from a semitransparent surface, is it easy to focus on HUD projections continuously. Finding stuff in the closet. This is so sci-fi. We'll see level 5 autonomous driving first. Heart rate (blood sugar, any other vital) monitor. Basically, it's a solved problem and a feature available commercially. You don't need to see heart rate continuously to be warned about an anomaly. Sound alarm works just as well if not better.