To me this drone only makes sense as an assassins weapon.
The drone only carries 100 rounds. Not enough for tactical operations
The speed and range also are not enough for tactical purposes.
But for targeted assassination it would be effective. The assassin could get close enough for the drone to fly in to a compound and unload its magazine in to the target. If the drone is lost it is of little consequence.
The article does not state the caliber of the weapon. But if it is 0.223 or larger a smaller caliber would be sufficient for assassination and may boost the chance of mission success.