This is a good spell to start the fight and pull enemies until level 12 when you can learn [Lava Burst]. Used against a foe with no speed boosting abilities at max range, you can cast 3 Lightning Bolts in the span of time it takes for a mob to reach you. You can even cast a Shock just as the 3rd Lightning Bolt finishes casting to max out damage against a pulled, incoming mob.
It is also more likely to use during combat because of its 2 second casting time as opposed to other classes' similar function spells ([Shadow Bolt], [Fireball]).
Hotfix (2016-09-23):Lightning Bolt (Elemental) damage increased by 23%.
Hotfix (2016-08-22):Lightning Bolt (Enhancement) damage has been increased to 30% Spell Power (was 25%).
Patch 7.0.3(2016-07-19): Cast time reduced from 2.5 sec to 2 sec for Elemental and Restoration, instant for Enhancement. Damage increased by 25% for Elemental and generates Maelstrom, and by 74% for Restoration. Damage for Enhancement depends on Maelstrom used. Mana cost removed.
Patch 6.2.3(2015-11-17): Damage has been increased by 4%.