From what I understand, I believe other commenters in this thread refer to AR as a combination of 'real' reality and computer generated overlays. This is opposed to VR where all of reality is generated. So when we talk about AR headsets we're talking about things akin to Google Glass or Microsoft Hololens if you're familiar with these products. In that sense you are never 'inside' AR (with a headset or phone), it simply augments what you currently experience with extra data. With a true AR headset it is still possible to interact with people in the real world, you can turn on/off the extra data easily (since you are still immersed in the real world) and the computer generated overlays fit in with your real surroundings in a way that is simple and intuitive. Granted such a headset does not yet exist, but I believe that is the end goal.
What you describe as 'stepping inside the Metaverse' with no possibility of interacting with the real world is exactly what VR is all about (full immersion). (As an aside, the Metaverse as described in Snow Crash is exactly this: a Virtual Reality.)
As for the headset vs phone debate, personally I believe that the applications of AR in a non-headset configuration will be limited. There are definitely applications for one-off utilities which don't require constant use (ie. don't require gorilla arm), but having it available at all times and transparently via some sort of headset is where I believe it will really be useful.
Another version would be something like the "darknet" in the book Daemon/Freedom by Daniel Suarez https://en.wikipedia.org/wiki/Freedom%E2%84%A2
Imagine the Metaverse exists, fully fledged, and there are two products which can access it:
1) A headset that you strap on your head, and you're "inside"
2) A picture frame that you can hold up and look through, and the Metaverse appears on the other side. You can reach behind the frame with your other hand, and it's then inside, and can touch stuff inside
Which will be more popular?
Now, I know a lot of VR enthusiasts are going say #1, but I suspect a lot of people will prefer #2. It has several benefits:
- No nausea
- If freaky shit starts happening, you can just look away or put the device down
- You can keep talking with real world people
- You can look back and forth between the Metaverse and the real world without taking your headset off or performing any kind of switch
- You can still make eye contact with people in the real world
- A bajillion people already have an iPhone
- There's nothing really to learn, the Metaverse is just a new app on your phone, not a whole new interaction paradigm
The downsides are two:
- Less immersive
- One of your hands is taken up
I can see the uses for both devices, but I predict the picture frame gets at least 50% of Metaverse interactions over the next decade, maybe more.