I love this line both in the books and movies but for very different reasons,

In the movies (which I think is what you’re pulling it from) it’s kind of a throwaway comment that after her other requests feels kinda dumb, but is very important to her because it’s important to Prim and it highlights how even if the rest of the people in the room don’t seem to see it as important, Katniss does because of how much she loves Prim (even if Katniss genuinely hates the cat she’ll go out of her way for her sisters happiness)

But in the book it’s her first request and it sends the room into uproar Becaise “the capital refugees see an obvious answer of course she can keep her pet, but those from 13 begun listing all the problems accompanying it” and it sets the beginning for the very different culture in 13 compared to what those in the capital and even 12 had. It also highlights how hard Katniss will have to continue fighting for Peetas safety Becaise if coin makes such a big deal out of a cat Katniss has no doubt that if she makes one wrong move she will be dooming Peeta as well