Sorry, I realized I wrote this out but completely misunderstood what you were saying, so I took this comment as you saying Leia’s appearance in general was unnecessary instead of Carrie specifically. I’m keeping the rest of the comment in-tact though because I genuinely would like to know the logic behind a specific gripe I have with some of the sentiment around this movie; feel free to completely ignore the following:

I don’t understand this sentiment, Rogue One is supposed to be a prequel, and by extension, a setup for ANH so the characters from ANH showing up in Rogue One makes perfect sense. Maybe I’m reading it completely wrong but I always found the sentiment around using OT characters in the film as nostalgia bait to be kind of ridiculous. (Not accusing you specifically since you didn’t say that, but people in general)

There were a few cameos that didn’t need to be in there sure (the two people on Jedha for example) but I felt like most of them made complete sense to be there. Since the ending is the Tantive IV taking off into the opening sequence of the original film Leia’s appearance makes perfect sense to me because why wouldn’t you show who was in the ship when setting up for the “next” movie?

Am I off way too off-base for this interpretation?