At the time, Bungie was known primarily as developers of Mac games, and The Fallen Lords was the first game they had. The use of lightning, huge electrical discharges, and stuff resembling them as a weapon to fry things with. This is one of the most common Elemental Powers and is part of the basic Fire/ Ice/ Lightning trio.
It' s also one of the handiest ones around; used for anything and everything that the writers can think of. For why this doesn' t work in Real Life, see the analysis page.