Oddly enough, artillery (from my limited experience) seems more valuable on offence than it does on the defensive. On the defensive the enemy is a continuously moving target so it's very rare that any artillery hits them. However, on the offensive the enemy often just stands there waiting for you to come. With artillery, it seems as though you remove a great deal of the advantage that comes with being the defender. On bridge battles it has also saved the day for me.

So, how does everyone use them? How should on exploit them to their full potential? Or are they simply not worth it, all things considered?