Hopefully someone can add to military interventions which I'm less familiar with - meanwhile, I wrote this answer on the very connected topic of Cuban medical diplomacy with one focus on Angola, and one on the influence of the regime's literacy campaigns on education. It's connected since both military and civil interventions were in some cases used in tandem; and since medical diplomacy has become more important with the end of Cuban military missions.

One additional point loosely tied to your question: medical diplomacy was and is very cost effective for Cuba in that training doctors and carrying out specific operations are comparatively not that expensive, but bring many diplomatic/economic advantages as I discuss there.

Hope this helps!