I think their timidity would make them reluctant to cooperate with the Borg. Once access to a Borg Ship occurred through proximity (like in battle), they would be very helpful in diagnosing, then creating covert programs which could be transmitted to the Borg Computer, which would disable Borg resources. Information which was collected when Data "interrogated" the Borg Network via Locutus, should have a positive impact on those objectives.