It doesn't take away the advantage of artillery. Bombardment with artillery in Civ3 does not risk the artillery unit. (Bombers may be at risk if the defender can shoot them down.) I can haul my artillery around and red-line every unit I meet, without ever risking losing a unit. (If I play as Korea, I can kill them, too.) They let you take out TOW and Mech Infantry units in a metropolis with only cavalry armies, so you can destroy a modern aged opponent while you are still in the middle ages. (You do need a giant stack of cannons for this, of course.)