My life would suck without you
But all (not Shadow Sky or Fog, but meh to the) activate abilities like sun activating Solar Power, rain activating Rain Dish or sandstorm activating Sand Sand Veil. Hail just lacks anything to really make it stand out imo.
Also Nica and I had a hail team battle today for Christmas, it was obvious that our teams had more Pokemon to counter hail Pokemon then abusers themselves. The whole battle was pretty fail in all.