To shut down or not to shut down PC

The IT folks here at the office recommend leaving our computers up and running 24/7 so that they can update software at any time. I’ve always been in favor of shutting down my desktop PC when I’m not in the office with the philosphy that when it’s shut down no one can hack it, plus it saves energy. If an update does come about the IT folks have the computers set to automatically update when they’re turned on and/or reconnected to the network if the PC is a laptop. What are the Pro’s and Con’sof leaving a PC up for automatic updates versus shutting it down? (besides just the updates potentially taking a while to load in the morning)