Just checked out https://autogradr.com/. When I clicked on Signup, it went to https://autogradr.app/signup. Is there a reason it's not in autogradr.com since you control the domain?

Also, it asked for my role with two choices "Instructor" or "Student". I'm paralysed, now because I could be an instructor for some, and a student for others. How will this dictate the future experience? Will I be able to switch roles? Will features of the one be unavailable for the other?