Great question @sheitner! As long as you have a compatible smart lock that works with Ring, it can arm and disarm the Alarm. In order to do this, the PIN must be entered on the smart lock, as locking/ unlocking in the app will not arm/ disarm the system.
In addition to needing to use the PIN, your lock PIN must of course be the same as the PIN used for your Alarm system, and the access code/ PIN must be synced from the app to the lock for it to work as intended with the Alarm. I hope this helps! 