One additional wrinkle is that ideally we would want the TAs to see the past answers for problems without having to act as the user. We don't want the TAs to see grades. In the setup above, because the student is acting as another student they could also see grades.
If we don't allow them to act as the student, then they can't even get to the webpage showing the problem, the number of attempts and the button to show past attempts.
If we don't allow them to act as the student, then they can't even get to the webpage showing the problem, the number of attempts and the button to show past attempts.