First, Paul tells us to pray for all saints. The Body of Christ is intricately connected regardless of where it is stationed in the world. When you pray for other believers, even those whom you do not know, you will be strengthening prayers for people that you do not know, you will reap prayers from people that you do not know.
Secondly, we are exhorted to pray for our point men. Leaders are prone to experience attacks that many believers never face. For this reason, we pray for them regularly because they can have an outsized impact on others!