Responses
If she refused there would probs be rumors about her rejecting an invitation from the Empress.
Rules of noble etiquette indicates that you cant reject an official invitation/order from royalty. If she didn't go that could have been taken as an insult to the Empress and caused alot of problems for the Dukedom. Basically putting Elle in danger.
when she doesnt have any advantage or goal by attending that empress' shit tea party.. a