It doesn't appear to be needed for C4 integration, but in my case I just have the lowest tier of alarm.com which has the monitoring bundled with it. (at least with my provider) You don't need the automation addon from alarm.com for the C4 integration - sales person insisted when I was signing up, but it's not needed. The app is ok, but I'm generally using C4 over 4sight to manage arm status. Proximity disarm via bluetooth from phones is handy.