No, it's a Mail Transport Agent (MTA) if you want to send emails yourself you need to be able to manage through put rates, SMTP connections and various other things.
On a basic level, when you connect to email servers such as gmail they will tell you at what rate you can send to them, 20,000 emails per hour for example, you need to be able to manage that otherwise they will black list you and your IP reputation will be harmed making it hard for you to send emails.