In some cases you need to record programs during a inconvenient time, e.g. after midnight. You dont want to keep your system running. I would be a good feature to shutdown the systems after the recording is finished.
This can be done now by vdr itself... but the idea behind lmce for most people is to keep the core running 24/7 so that it can provide all the monitoring and services to the devices on your network.
If you think this requirement is important i would suggest that you create a Mantis feature request here http://mantis.linuxmce.org