Why is the A-10 Thunderbolt's Gatling gun use depleted Uranium for ammunition?

The A-10 is known sometimes as the "tank killer" Ammunition that is tipped with depleted uranium burns hotter on impact and s and literally burns holes through the heavy armour of tanks and troop carriers much better than conventional ammunition. It is also used with bombs and I have seen the French built concrete hangers that Saddam Hussein built for his fighters that we destroyed in DESERT STORM. They were several feet thick and reinforced concrete and the bombs destroyed them while burning right through the concrete.