Counter Battery fire hits

[Walrus]

Yes, they can eventually take out enemy off-board arty.

You need to leave the unit un-targeted. The skill of your arty unit, and also your FOO unit is the main factor when deciding how much damage you can do.

Your arty must have longer range than the enemy arty. This is most important.

If you use the replay function, to watch the enemy's turn and also your own arty landing, you should see a message if there has been any effective counter battery arty by your arty units.

Whether it is a waste is up to you to decide but it definitely works.