Because they were also afraid that a seemingly insignificant evil ghost might suddenly launch a sneak attack, which could be deadly!
The terrifying thing about Fan Wu was that he wasn't afraid of being ambushed.
Even if he was attacked in his vital points by some dishonorable evil ghost, it would be of no consequence to him.
He turned the Demon-slaying Sword into a storm of blades.
Every evil ghost that touched the storm of blades would turn into ashes.
Their vulnerable bodies, once touching the Demon-slaying Sword, were bound to die upon contact!
They had no ability to resist at all!
Unless these common evil ghosts possessed the "Power" and "Life" attributes like those of the Ghost Generals, they might survive an extra strike from the Demon-slaying Sword. If Fan Wu's blow was slightly off, they might even endure two strikes.
Unfortunately, they didn't have them.
For both cultivators and evil ghosts, a "Power" attribute over 50 was like a chasm!