Purpose Of Energy Negating Items

hi i have a req 12 energy +12 energy -5 armor +5 fire focus item thats gold. i was wondering wat purpose the negative energy served.

Negative energy is meant as a drawback, as you're getting an unconditional bonus to go along with it. On offhands it's +armor, and on weapons it's +% damage. It's meant to be a deterrant, however they do have a positive use, when dealing with edenial. When you're being edenied, switch to your weapon set with the least amount of total energy. You'll reach 0 energy very quickly, and once you hit 0 you can't go any lower. Any attempt to further edeny you will be useless, so as soon as they're done, switch back to your normal set and you'll have a bunch of usable energy. This tactic is very common among monks, and is known as focus swapping or weapon switching.