Why dedicate a separate category to the sanctions of arms embargoes? What makes them special in the context of other sanction measures available to the international community and the EU?

They are called for in crises situations as possibly the least-objectionable restrictive measure to clearly communicate that one does not support a violent escalation between the target parties. They are used often, in fact, the most often out of any other sanction type by the UN and frequently by the EU and many state actors. 

Their prolific and unobjectionable use bears investigation into the type of effects to be expected of an effective arms embargo but also brings the question of whether an effective arms embargo (e.g. one being complied with by the senders, monitored, and enforced) is actually the right and proper tool to be implemented. 

The lecture further illustrates the main trafficking routes relevant to conflicts with impact on the EU and the EU reaction to the deficiencies of this tool, culminating in the debate over the Common position on arms exports and the Arms Trade Treaty.