There are times when it would be helpful to reply to a ticket, but to have the reply delivered to the ticket requester sometime in the future. One use case for this is if a ticket is being worked on over a weekend or holiday and you don't want to disturb the user until the next business day (Monday, for example). Same thing for private notes to other agents. You might want to communicate via a ticket not with another agent, but they could be on personal time off or it's late at night and you don't want to bother them until the morning.
So when replying or adding a note, it would be a great feature to allow for future delivery by setting the date and time you would like the email with the reply or note delivered to the requester or agent.