Ben,
All that does is refresh your message inbox. So if someone sent you a message you wouldn't know it unless you actively checked a different message, clicked on the Message button at the far left which is much larger or clicked on that one.
There are two issues here:
1. Is it should say "Messages" and not "Email."
2. It should definitely have Auto Refresh anyway so you don't miss important messages until 9PM if then.
3. Plus, your staff sometimes will miss them.
I hate hearing from my staff, "I sent you a message." But, for important messages, sometimes you have to. So play around with the green messages icon between Schedule and Search at the top left and the button you are referring to.
Welcome to AC Ben!
