Well they can receive and display a video input from an external module some of those modules are networked and provide sensor fusion.
I’ve seen modules that stream live navigation data, blue force tracking and video feeds. The only difference is that it’s a bulky external module which connected via a cable.
You also have small clip on modules for things like thermal imaging and video recording/streaming.
Other than that the PVS-21 is an AR headset the intensified image is projected on the lenses which allows the user to see through the headset just like any AR headset and it can display data from an external source.
https://www.steiner-defense.com/imaging-systems/cehud-confor...
Edit: It’s just not as sexy and tech loaded as the hololense but honestly I think the PVS-21 model is better the interface with the HMD is optical and the modules become smaller and more capable as technology advances.
It looks like what used to take an external box the size of a hand radio is now wireless has an OLED display and fits in the screw cap of the optical interface port.
