Seminary refines a girl and after a year there, they are more responsible and independent, ready to maintain a house. Some seminaries require the girls to cook one meal a day- it prepares them to cook for their families 3 meals a day. Girls also have to do their own laundry, take care of finding their own Shabbos plans, shop for food and do errands all while managing their school work. Besides for the spiritual growth that enhances almost every girl I have met who has gone, this more tangible benefit is seen.
By the way–
Look into Touro (specifically Flatbush)- they have grants for those who will be going there after a year in seminary but have issues paying for seminary.