What are the advantages of the battering ram?
the battering ram was only used to basecly open castle walls by force and well they were used so most of the army wouldn't get killed outside the castle by archers. it was basecly so the opposing army can get the advantage of bringing the fight inside the castle
A scaling tower was used in ancient wars to allow soldiers to reach the top of an enemies' town or fortress walls. If a battering ram is attached to it, then scaling the walls over an entrance to a fortress or city plus using the battering ram to break open the forts doors can be accomplished. This type of war "machines" were used into the Middle Ages.
As a device intended to knock down a sealed door of some kind, a battering ram is indeed a simple machine; or, at least, it can be. For, while sophisticated battering rams have been created and utilized, the trunk of a tree can serve just as well, when and where the gate or gateway to be rammed open is appropriately sized.