For displaying flat content it is indeed just a kind of monitor simulator, but that is hardly the point of VR. When looking at spatial content it is fundamentally different from a monitor, you can move your head to see the object from different angles, that is a game changer. But the use cases outside gaming and simulation are not obvious. CAD and certain visualisations is all I can think of.
It would be nice to move about my home with computing interfaces arbitrarily affixed to "dumb" objects. Sure, the computer generally comes to me as needed, but as a pacer, I think better when I can move around, attaching different thinking modalities to different physical spaces. If those physical spaces also shared their context, that would be pretty great.
It would be great to ditch the phone, ditch the watch, ditch the laptop, ditch the tv, for mutable device that's whatever I want it to be wherever I am.
The big downside is that I don't want a big sweaty device attached to my head, fogging up my vision.
None of that is really spatial in the way that you're describing, but it's incredibly spatial from a user perspective.
