If you look closely at this, you will see that it is not a reaction control system. It is a "circulation control" system where the blown air does not push the aircraft one way or the other - as in a reaction control system - but rather uses high pressure air to modify the airflow on the (non-moving) control surfaces and thus increase their lift in one direction or the other to affect control. This is similar to the "blown flaps" that were used on some STOL concept aircraft previously developed...

The major benefit is the elimination of the weight and complexity necessary for heavy hinged surfaces (and actuators) which are replaced by simple slots in the surfaces and some airflow control valves.

Bob