I think the Oliphant angle is bunk, as these doors are everywhere and anywhere, including balconies on Kikowani and inside Squidhenge.
I mean, yeah, why would exactly autonomous vehicles need to read barcodes anyway in the year 2552? : D Or any tech for that matter? In many ways the angle doesn't make sense, but then again it might not need to make sense to create an atmosphere of "these people have barcode on their walls 'cause they're so automated and sci-fi".
I believe it is just a technique to use the same assets on multiple doors and not have them all (appear to) say the same thing. For example, if the sign read "Cafeteria" instead, you'd think "Hmm. Why are there hundreds of cafeterias in Mombasa streets?". Instead, you see a complex barcode, and you assume them to be different, providing the illusion of many different labels throughout the city. Now, we of course just see 3 J banners, but the average player is going to see them as unique to the door they are over, which provides great immersion.
Now, could a dev use this opportunity to shove an egg in there? Sure, but at this point I doubt that's the case.
Oh, that's a great point!! When you make a texture that seems complex enough, even if they're mundane and used a lot people might not notice. Also, it again is creating atmosphere in the sense that something could be written there that has a function, and that something is going on in the city, instead of just using "blank_concrete_slab_19" -texture and making a bustling city's walls look empty. Nice.
