Basically its just screen yes. It's just convenient and more portable to do it this way. Small desktop screen also exist and are used to peek on what the FPV operator is seeing.

Yeah I'd much rather use an xreal air or something. You can still see if someone (or an enemy drone) comes to kill you. AR is much better for this.

Probably you want the pilot to be 100% focused on the piloting. Someone else can look around and try to keep the pilot safe.

Also it's not like the pilot has to be exposed.

No, the latency is too high.

There are dedicated devices for this - much lighter, external battery (same as the drones use), etc. I use a Skyzone 04X.

They hide in bunkers and have other infantrycwith them if that’s not the case.