Is it a game or a sim? Many argues that it is in fact a game and not a sim. But why should that matter in this context even? Like I said before... Third person flight with basic controls, nu HUD, no weapons, no firing mechanisms, no chaffs... Nothing. Just flight controls.
How is that giving any advantage?
I don't think it is about immersion either or breaking realism. I think it's the very concept of having a "gamey" third person camera itself that people have issues with.
I would say that Elite Dangerous is a simulator. It simulates its own world and its own physical law and constraints etc, but id argue its still a sim. Same as how mechwarrior series is a mech sim, as opposed to say, armoured core which is a mech game.
At the end of the day the experience revolves around piloting a fictional craft which it is simulating under its own rules.
For this effect to hold and to keep what makes a core element of the game, they have to be careful to maintain the illusion. That is why it is important.
This is something Elite Dangerous does very well and something I hope it continues to grow and focus on. The feeling of the GUI in VR is great. I play Elite purely for that, to get a feeling im in some kinda sci fi movie. Just as I play DCS to get a feeling of piloting a real life MIG-21 or some other complex aircraft.
Talking about DCS and Mechwarrior to continue the trend - external cameras can offer great advantages in seeing where opponents are coming from. In DCS obviously being able to hit 'external' camera mode, and now your usually extremely limited visibility Mig can see 360 degrees all around it, for enemies coming towards it in its blindspots. That removes alot of the restrictions of flying that particular aircraft. It is also why 95% of servers run with it disabled.
With Mechwarrior Online, you can use the camera to look over terrain not normallyable to be seen over.
For example in Elite, one of the biggest selling features of the Asp for me is its high visiblity cockpit. Same for the Eagle. If you have flown an eagle in VR you will know just how awesome the bubble canopy is to use.
So with this all said, I can only at a stretch get behind a camera that has limited abilities like you state, purely for screenshots etc etc.