One big reason I think I haven’t gotten a whole lot of responses is that many organizations have either a non-IU affiliated gmail account or, worse yet, the president or vice president’s student email. A non-IU affiliated gmail account is the better of these two options, but I think there are still problems there. For example, a non-IU gmail seems riskier to send messages to than an IU account. There could also be the potential annoyance of someone syncing their calendar to the gmail account so that the next person has random notifications popping up.
A student’s individual email account clearly isn’t any better for the obvious reason that it’s unusable once the student graduates, but I’ve seen plenty of organizations that do this.