I think the descriptions show these are YA and meant to attract teenage/slightly older girls who want to imagine glorious clothes and the like. It's pretty escapist.

I doubt Collins was trying to "draw in" girls via a few token descriptions of clothing or how it's escapist (how is it escapist btw?). The descriptions of pretty frocks, frills and all were more meant to highlight more of how Katniss views it as excess, unneccesary, and does not see the importance of appearance to the Capitol citizens. It's more of trying to bring about how clothes, fashion were inconsequential, especially when weighted against those in the Districts starving and barely surviving.