You might be able to get more tooltip DPS out of a rare bow or Windripper, however using Voltaxic has a number of inherent advantages. Firstly you cannot damage yourself with reflect as chaos damage doesn't reflect, but the most noticeable aspect is that Chaos Resistance is much rarer than elemental resistances and usually shows in lower percentages. This means that unlike elemental builds, both attack and spell based, who will often be slowed down substantially by elemental resistant mobs if they don't invest heavily in workarounds like penetration and curses, you will cut through elite and magic packs as well as resistance maps without noticing any difference.