I also don't think the hat in that photo would be flat against the cat's head, because it's a human-shaped hat on a non-human-shaped head, whereas some of the Miqo'te hats don't have that excuse. Things like wizard hats would be fine (and actually I think they should have not added ear points to the ones that have them, because they're always misplaced), but tight-fitting things like the baseball cap have no extra room inside.