The system is there so you can make use of some buffs like Peace of Mind, making your character move before that boss so it can throw some important spell so your entire party wont be wiped. I.e. you are in situation where you either stun an enemy or die with your archer but your archer is the only one that has something to knock him down and it has Initiative of 22. Boss has 23 initiative. You can use a spell or Wits potion to change move order to let it become in your favour.
Your tactical skills improve, crafting becomes more useful since because of it you had that Wits potion. You win fight and continue playing.