Why the A-10?
Because the A-10 is the last dedicated attack aircraft currently in active service with the U.S. military, it's the only one designed specifically to provide close air support to ground forces.
Why not an armed helicopter?
Because armed helicopters aren't as fast as the A-10, don't carry as much ordinance, and don't have the A-10's survivability.
Most importantly, armed helicopters don't have the range of the A-10.
With just one rocket pod and 1,150 rounds for its 30mm cannon, the A-10's combat radius can reach 900 kilometers, with a range of over 3,000 kilometers.
In other words, these two A-10s can take a basic load of munitions and a full fuel load and accompany an E-6B electronic warfare aircraft from a distant airfield to Malakal to conduct a precise air-to-ground strike.
So why only two A-10s and one E6B came to Malakal?