War machines in Heroes V.

A tent and a catapult are really helpful in small battles, when you need to quickly eliminate, say, 7 groups of 2 Imps :kool. Then, every insignificant shot helps. Also, they sometimes distract the enemy, who ignores the units and goes straight for them.

Well, there's no need to talk about the usefulness of a cart in prolonged battles (especially when taking a castle).