It is the interiors that are visible through windows or glass fronted buildings that are the most important. If I could see inside the terminal (or any other building) from my real world plane as I taxi in (or when I am at the gate), then I want to see it in the simulator. It adds a massive amount to the immersion for me, although I understand that it does not do the same for everyone. It is difficult to describe, but it just makes me feel better when there is detailed interior modelling (even if I am not able to see all of it from my plane), or when all of the airport textures are high resolution (even on a small shed at the far end of the airport that I will never get to see close up unless I take a little drone flight over there). If the texture on this hypothetical shed were low resolution, it may not affect my day to day business of flying, but I would know that it was low resolution, and it would bug me!

Edited February 5, 20242 yr by Christopher Low

Attention to detail shows me that the developer is stepping up to the plate and not just phoning it in. 

13 hours ago, JYW said:

But I'll be devils advocate and ask whether wandering around a fully detailed departure lounge, looking at JPG departure boards , buying virtual duty-free and pretending you're off to Majorca is really fundamental to realistic flight simulation?

Yes, yes it is (IMO).
Here's why:

Stand 9 at EICK.

And that goes the same for T5 at EGLL, T2 at EDDK, T2 at KDCA, T1 and T3 at CYYZ, T2 at VVNB... Anywhere there is a view from the aircraft stands through the glass cladding and into the terminal building.