Originally Posted by
Rucati
Secondary stats are just better, so there's no reason to put a main stat gem in when the secondary stats are more valuable. Int/Agi/Str add damage or healing, but Versatility adds damage/healing and also reduces damage taken, and for some specs Mastery is incredibly effective too (though Versatility is usually best for PvP).
The corrupted effect on that will still work, but it has less value than pieces with +Versatility or Gushing Wounds. So it's still fine to use, but it isn't worth the corruption unless it's all you have.