The main use for the duplicator will just be keeping records of the sermons. Traditionally, churches have always recorded messages in one form or another. Audio recordings are popular, but they leave a lot to be desired. If props are used on stage, they are invisible to the listening audience. Also, the delivery of the message, which can often be as impactful as the words themselves, is lost. A sermon that is recorded on a DVD will make the person who watches it feel like they were really there.
The DVDs will also be helpful if there are members of your congregation who can no longer come to the services for one reason or another. Perhaps they are elderly and the trip just takes too much out of them. If they have been coming to the church for 50 years, though, they will very much want to be a part of it. A DVD allows them to get the closest thing to the true experience so they do not feel abandoned.