Popular with mages as they're relatively cheap to buy and deal decent amounts of damages, allowing a mage to kill relatively strong monsters such as Cyclops and Minotaur Guards which their melee power is not sufficient for.
Many sorcerers make them to sell (though those at level 45 and above can learn the spellSudden Death which is easier to sell and often better money-mana, though this depends on the world).
Druids rarely make them to sell once above level 28, because they can make Icicles from this level onwards, which are easier to sell and have a higher price.
Before the Major Game Update 8.1 it had less charges (only 5) but also took less mana to make (just 280). It also required magic level 4 to use, rather than the current 3. The magical formula was adori gran but has since changed to adori vis to better match the new element system.