Yeah but you are wrong. At worst it's the same. After I talk to Miranda if I go to talk to her again the conversation is one off comments of I'm busy or whatever. If there is some change to be discussed then new conversation pops. The same effing thing happens if you can talk to them anywhere. Except they may add a handful of context sensitive lines. But otherwise it will be identical.
I actually get Puncher's point in this. In fact, I was thinking of Miranda's ME2 conversations when reading the previous posts. When you talk to her, the characters move around, they use objects (e.g. they may sit on the couch or a chair or look out the window, pondering). All these action help the flow of the conversation and establish a tone and in some cases an emotional background to the characters and the topics they are talking about. It would be tough to replicate this if I could initiate the same conversation on the mountain slope of an icy planet. Or even worse, having it in an inappropriate context. Would Miranda really want to talk about the contents of the emails she now sends to her sister while we are on a derilict collector ship? I think not. And if I can just get the default answer, then there is no point in talking to them really.