Yes, what it does is break the stove draft with a slipstream of room air to prevent overfirering the unit. Typically they are set so the draft does not exceed a setpoint, around .06 for a hand fired. It's sort of like a boilers water pressure safety valve, they are safety valves for tiny amounts of negative pressure that control the stoves "breathing". The addition of a barometric damper is pretty much required with anthracite for saftey reasons. The units generally perform better and use less coal too.
It has no real relationship to the operation of your plate damper in the stovepipe.