Side note, but related, because these characters don't go with you: there's a bit of character banter-style development with Josie and Cullen (between the two of them, and also between them and other party NPCs) that plays out entirely through the conversations they have with the people standing next to their desks. Same deal, completely RNG. I have spent a lot of time in Cullen's office (not always on his desk, thank you very much
), but it took the 5th character to see the one in which Cole sends him a message about Uldred, for example. It blew my mind, in context--and also made something Cole says in conversation if you turn him into a Real Boy finally make damned sense (when he says "I can see why some things I might say would bother Cullen" I was... er, what??? until I had RNG throw up the deskside Cole message, then it was, like, "oooooooooh"). There's also a string in which Josie is trying to find the perfect gift for the Commander (his birthday happened a ways before the game starts, in case anyone's wondering), that I've seen what I think might be the entire string.... once?
There are also 2 not-Inquis-related relationships between party members/advisors (if you don't romance them yourself) that will only trigger if you have them around and hear the banter strings--in the case of one coupling (at least, I haven't had the other happen yet), when you get to the end of the banter string, if you are bffs with one (or both) of them, you can then have a really amusing/touching conversation back at Skyhold with one (or both) of them about it (and I had a complete d'aawwww moment with one of them that i didn't see coming because of that). So, yes, banter is important, and it does fill in the characters. It even changes the conversations you have with them both at the post-story after-party. It is not just radio DJs firing, and these things are "hidden" behind the banter, hong--because they don't happen otherwise.