Getting special forces or allies on the ground is not always an option. In countries like Somalia and Yemen where there have been conflicts between factions the authorities will not always cooperate and even if they do they may not control the territory where the strike team would need to operate. There will also be many times where it is simply too dangerous to try and snatch someone. If that person is a danger they need to be stopped in the quickest way possible; and that will be by the use of the UAV that is already far above monitoring the target.