What is the use of mortar?

Mortars were used to support ground troops during invasions, or helping them defend a position be using 'danger close' mortar strikes (danger close meaning mortar strikes, air strikes or artillery strike close to friendly ground troops) sealing off the route the enemy used to attack. Also, mortar strike could be used to 'soften up' enemy ground defenses so that the friendly ground troops attack would be made easier. Mortar strikes would use coordinates acquired by ground troops and sent over the radio to signal where the mortar strike would land. Mortar shells were just like missiles, but you could throw one, after activating it, and use it as a super powerful hand grenade when needed.