>>23311953 Commonly brothels used to employ young orphan and runaway girls by having them do the chores in exchange for food and boarding. They were considered too young for prostitution work but it wouldn't be unusual to be "promoted" when they came of age. They were not legally bound to the brothel and were technically free to go at any time, but brothels could easily pressure these girls into prostitution for the brothel. Basically the young maid were whores in training. The maid attire is extravagant for the show, but it's not incomprehensible to imagine that an establishment would want to look a bit classier than a your common whorehouse.
Sincerely,
Char Aznable, Chief of Sex Tourism Department for the Principality of Zeon