If this is about your daughter, why are you asking about compensation and what you can get out of it? Besides, whether required or not, WN gave here a meal voucher. What else would you want her to have. Seven hours is a long time, but there really is not much else to be had. I certainly hope that she had enough money with her to purchase a meal if things went wrong.
It is great that WN located her and that someone had the time to take her under their wing. But, one must plan on having to handle the situation on one's own. What was the plan here had the flight been cancelled and your daughter stuck at BWI? Things do happen when you travel and one has to plan ahead.
To answer your question, yes, she could have requested a refund of her WN ticket and then purchased anything else she wanted to purchase. But, WN is the only carrier which services SDF nonstop from BWI, so any other carrier would have meant yet another connection.