The problem with the Horror is it costs 10 qi and an action (not explicitly stated, but it basically has to if there's any consistency) for a relatively fragile and soft-hitting body armed with a couple techniques it uses worse than we do. Deepwood Vitality is an alright fit because the user is less important, but even then the dispel component is weaker; we just don't care because we have enough dispel sources that it's not a part of any strategy. However, if something is dealing health damage to us or Zhengui consistently, we're probably already boned and the enemy will take out the Horror effortlessly regardless.
I don't particularly see the action cost as a problem, and depending on who it is targeting, it is not simply a soft hitting summon that uses techniques worse than we do. The problem is the fact that people are expecting it to target and deal with a monster when it would do better targeting the monster's spirit companions.
Contrary to popular belief, Zhengui will most likely have trouble dealing with spirit animals of the vast majority of competitors. Our debuffs will help, but it will most likely be a tough fight for him given that he is late yellow and most of them are going to be either early green or appraisal green. We are talking 2 to 4 auto's here on top of Zhengui, with better techniques and dice pools.
A green level assistant to Zhengui that provides damage and a support art might very well allow Zhengui to win the fight, or win it faster, than he normally should and then Zhengui can come over to help us.
In the spirit beast on spirit beast fight, the Horror is a decently tough body that can pack a wallop while providing a solid debuff and additional defense to the entire field.
I will admit that 10 qi is a lot. It is a significant investment for Ling Qi to make in order to change the scope of the battlefield. Which means, however, that Ling Qi won't throw the Horror out willy-nilly. It will be used when Ling Qi believes it offers enough of an advantage to swing the fight, and that the cost is worth it. This could arise in any number of situations, but the cost is a deterrent to wild use and aligns the Horror as a more unexpected ploy used to trick, deceive, or swing a fight in her favor.
Outside contexts also favor using the Horror before the Monsters in maybe a less "make-or-break" situation. It creates the impression that we have tools that nobody knows about, that could be devastating to an opponent. People don't know how many of the Horrors we have, nor do they know if we have a stronger version waiting in the wings. Since people will be watching our fights, it may make a higher level opponent approach the fight more cautiously. They may act under the assumption that we have a stronger version, which might make them act more cautious than they perhaps should act.
It possesses a plethora of tactical and strategic uses that we can use to manipulate people's expectations of how our fight with them will go.
