I really felt for her friends in the Paris shopping video. Katherine made a comment saying they always stick together when they go away, except when she goes on a designer shopping trip. She said it very pointedly and very much in the tone that suggests the friends can’t do it.
Looking at her friends, they all seem to be working, living independently, and in relationships/having babies etc. so I’m guessing that, like most younger people, they’re faced with big rent or mortgages, and have massive bills. I’m also guessing that they’d love to be able to afford to shop in expensive stores but, as is the case for 99% of people, they can’t/don’t prioritise it.
Then Katherine swoops in with her benefits money, extra from working part time, she isn’t paying a mortgage, doesn’t seem to contribute anything towards her mothers’ house, and so has plenty of Gucci money, but she rubs it in the friends’ faces by pointing out that she’s the only one who can do those shopping trips while they’re away.