Arcane Energy is primarily derived from a mysterious energy supplied by genes and cells, and can basically be considered similar to one's physical strength; it's fine for casual use and recovers quickly, but once in combat, with all the running, jumping, and fighting, recovery becomes very difficult.
Martial Artists continually generate new Qi Energy as long as they maintain physical exertion and their cells are stimulated.
A Mage can stand still and burn through their Mana Bar, and still casually pull out an AK to give you a burst of fire.
Those who specialize in Arcane Energy aren't so lucky, unless it's a passive type of Arcane Energy; to put it exaggeratedly, if you want to wait for Arcane Energy to recover during battle, by the time your Arcane Energy value is full, you could have written more than twenty pages of your family tree.
