Do students really want to eat in halls for three meals a day, seven days a week though?
That was dd's worry. If she'd paid, she would want to feel that she was eating there or it would be a waste of money.
I could also see her turning down someone suggesting they meet for lunch/dinner elsewhere because that would be paying for dinner twice, so could actually be unhelpful for her socialising.
When I lived in college over 3 years I had breakfast exactly twice (first morning and when I'd been up all night), lunch occasionally (usually when my bread was too far gone for even toast) and usually dinner. We paid for what we ate, so that suited me.
It would have increased my spending considerably if I'd eaten every meal in. I used to spend roughly £5 a week on food on top of the catered.
That paid for: 2 pints of milk, 1 loaf of bread, 1 packet of biscuits, 1 bottle of cola, 1 set of yoghurts, whatever fruit was on offer and I used to get one treat (or something I was running low on like cereal) with any spare money.
Our catering was considered cheap, but it would have still come to £10 for breakfast and lunch for a week.