>>23310998Well if the gown is for trapping hot air then it would need to be almost completely enclosed.
The fur on mammals is used as a form of insulation, that can either keep it warm or cool depending on the environment. Given that Gards are most likely mammals, it would probably be safe to say that the gown is a form of insulation, given their low body mass. It also could help blocking uv rays, given the light tone of their skin.