For me the only advantage to a managed switch is to be able to virtually segregate traffic by individual ports. So for my main switch in the house I have a gigabit layer 3 managed switch which in the past when I had 2 internet providers allowed me to keep the connections separated.
For cctv if using BI the I don’t think you need a managed switch, simply put an extra network card in your server and this should allow you to keep the camera traffic separated from the rest of the traffic. So on the server use 1 network card and connect it to the switch that your cameras are connected to and then the other card connect it to the network in your house.