Hu Fei had miscalculated the balance of power between the two sides. In her view, although Zhou Tian might suffer some losses at the hands of the divine beasts initially, once Zhou Tian regained the feeling from before, not to mention defeating those divine beasts, it wouldn't be impossible to kill them all.
In fact, the war between Zhou Tian and the three-headed divine beasts ended in total defeat. If it hadn't been for the divine beasts acting separately, Zhou Tian might not have been able to defeat even the first Qilin he had slain.
Another crucial point was that Hu Fei, having underestimated the strength of the divine beasts, did not anticipate they would continue to destroy Zhou Tian's territory. And with their strength, they would devastate Zhou Tian's land so thoroughly. If Zhou Tian hadn't ultimately survived the encounter with the three-headed divine beasts, the continent under his control might have been on the verge of complete annihilation at their hands.