As Bert pointed out, Exchange is essentially your own mini-Gmail/Hotmail. You don't have to give out your email address to your patients. It just centralizes everything when your email account or your staff's accounts can be centrally managed with your Windows account. You control your mailbox size, attachment size, joint accounts, and all of that. Links up with your phone as well.

We have a joint staff account. staff@driluthra.org (which is shared between people at the front desk). Personal emails are not given out. Patient's are not emailed directly. Like you said, if that was the case. We would be reading emails all day.

Exchange is more than email though: it has a calendar, contacts, tasks. All of that in one place. Basically, it's your own little GMail/Hotmail which you have in house, not on someone else's server. Your internal messaging is secure. Gmail is not obligated to protect your emails. More control for you basically.