If this is what people really want to do with HoloLens then I despair for the future of the world. Here are a couple of app ideas for medical/health things:
Emergency Assistance App - calls an ambulance and/or guides you through emergency procedures like CPR, with extra assistance from emergency responders via Skype.
Parkinson's Assist App - many Parkinson's sufferers need a little help to get themselves moving. An app could provides lines on the path ahead of them, which helps them get their feet moving.
In general I want HoloLens to replace my tablet and maybe my smartphone, too (if it has 4G/LTE). I'll want it to handle all my communication - calls, SMS and email - as well as navigation, calendar, etc. I also want to use it instead of my computer monitor to watch videos and streaming TV/movies. It could replace my big screen TV by projecting onto a wall, which I would paint black to maximise the image quality, as well as being able to project content from my DVR, using DLNA. That way I could watch free-to-air TV and DVDs with my HoloLens.
That's the bottom line for me - I don't see that it needs to do anything especially amazing because it will be able to do all the mundane things in an amazing way. And that is how I think it will succeed (or fail).