isnt it than ineffectivly? it istn much micro to aim the target you want...sure..you wouldent use it everytime its cd is ready...but you can wisely choose and could destroy blobbs or tanks while repairing.
Counter battery starts the moment an enemy barrage ability is activated. It already starts aiming and firing while the enemy indirect fire / arty piece is still setting up, so it actually has a much higher chance to hit mobile units. That said, I don't think it's accurate enough to consistantly counter mobile artillery or rocket systems. The Priest is basically immune anyway.