I'm able to schedule messages and set easy reminders for myself.
I often work odd hours, so I'll find myself responding to an email at 10 or 11pm. I don't want to set an expectation that I can be reached at all hours or that I work 24/7, so if I do write an email late at night, I'll just schedule it to send in the morning of the following day.
Similarly, if I catch an email right away that I can respond to, I'll schedule it to send 10 minutes later, so that my reponse-time is set at a reasonable rate. Review collected by and hosted on G2.com.