In some situations, getting the parental income information can make for an awkward conversation. If the students assume they won't get in for absolutely free, they might decide against asking their parents probing financial questions.

This is different than the FAFSA. When I last filled it out, the FAFSA had an option for you to send a link to your parents, so they could fill in their information without disclosing it to you. Unfortunately, money is a taboo topic in American families, and I don't doubt that many applicants feel more comfortable using this option.